LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


GIFT   OK" 


Mrs.  SARAH  P.  WALS WORTH. 

Received  October,  1894. 
Accessions  Afo.LftT     Cfes  M). 


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foftJTIESITT] 


SCIENTIFIC  AGRICULTURE, 


OR    THE    ELEMENTS    OF 


CHEMISTRY,  GEOLOGY, 

BOTANY  AND  METEOROLOGY, 

™.;ot 

PRACTICAL  AGRICULTURE 


BY  M.  M.  RODGERS,  M.  D., 
AUTHOR  OF  "AGRICULTURAL  CHEMISTRY,"  "PHYSICAL  EDUCATION 

AND  MEDICAL  MANAGEMENT  OF  CHILDREN,"  &C. 


ILLUSTRATED  BY  NUMEROUS  ENGRAVINGS,  &  A  COPIOUS  GLOSSARY. 


Nature  maintains  uniformity  in  the  operation  of  all  her  laws,  and  produces  nothing 
by  chance :  whenever,  th-  refore,  we  observe  an  apparent  exception  to  this  prin- 
ciple, it  is  due  to  deficiency  of  knowledge  or  error  in  conclusion.    And  who- 
tver  pi'actically  disregards  this  truth,  and  rests  his  hopes  upon  contingent 
events,  will  be  compelled  to  correct  his  error  at  his  own  cost. 


ROCHESTER: 

PUBLISHED   BY  ERASTUS   DARROW, 

CORNER  OF  MAIN  &  ST.  PAUL  STREETS. 

1848. 


;l/J^ 


JOEHUC: 

Entered  according  to  Act  of  Congress,  in  the  year  of  our  Lord 
one  thousand  eight  hundred  and  forty-eight, 

BY     ERASTUS     D ARROW, 

in  the  Clerk's  Office  of  the  District  Court  of  the  Northern  District 
of  New  York. 


BESTON  &  FISHER,  PRINTERS, 
Reynolds'  Arcade,  Rochester. 


TO 


HON.    ZADOC    PRATT, 


THIS  VOLUME  IS  RESPECTFULLY  DEDICATED  BY 


THE  AUTHOR. 


PREFACE 


No  apology  ought  to  be  required  for  the  appearance  of  a  work  like 
this :  the  importance  of  the  subjects  discussed  should  secure  at  least  an 
impartial  examination. 

But  from  the  humiliating  consciousness  which  the  author  feels  of  his 
own  inability  to  do  justice  to  so  difficult  a  task,  he  is  induced  to  say 
something  by  way  of  explanation,  in  order  if  possible,  to  put  himself 
upon  friendly  terms  with  his  readers.  The  importance  of  an  enter- 
prise, however,  furnishes  no  reason  to  an  incompetent  person  for  at- 
tempting its  prosecution. 

If,  after  the  book  has  passed  the  trial  of  the  public  prosecutors  in  be- 
half of  science,  the  critics,— they  shall  decide  against  it,  the  author  has 
no  alternative,  but  must  plead  guilty:  neither  will  he  claim  indulgence 
on  the  ground  of  its  being  the  first  offence,  or  plead,  in  extenuation  of 
his  fault,  his  ignorance  of  the  law  in  relation  to  the  case. 

But  a  sincere  desire,  (augmented  by  personal  considerations,)  to  aid  in 
the  diffusion  and  cultivation  of  science,  has  induced  him  to  make  au 
effort,  which  may  not  be  regarded  by  liberal  minds  as  altogether  in- 
excusable. 

The  practice  of  issuing  crude  and  imperfect  books,  is  a  fault  quite 
too  prevalent  at  the  present  day :  there  are  already  too  many  mere 
alphabets  of  science,  abridgements,  and  books  of  learning  made  easy ; 
their  tendency  is  to  make  conceited  and  superficial  scholars,  without 
the  labor  of  personal  observation  and  patient  study. 

But  the  elements  of  any  science  may  be  so  explained  and  arranged, 
as  to  give  a  synopsis  which  may  be  of  much  service  to  the  student ; 
and  when  these  elements  are  learned,  he  has  laid  the  foundation  for 
future  advancement  by  his  own  observation.  Plainness  and  brevity  have 
been  studied,  and  technical  language  avoided  as  much  as  possible ;  a 
glossary  has  been  appended  which  explains  such  technical  terms  as 

1* 


VI  PREFACE. 

.were  indispeusible.  It  is  needless  to  say,  that  a  treatise  on  science 
cannot  be  entirely  divested  of  all  difficulties,  and  couched  in  language 
which  is  at  once  simple  and  expressive. 

It  was  deemed  better  to  give  the  rudiments  of  each  sciencej  in  a 
separate  systematic  treatise,  than  to  intersperse  them  through  the  whole 
book  without  order  or  method.  A  reader  will  profit  more  to  have  the 
principles  given  in  this  way,  that  he  may  apply  them  himself, — than  he 
will  to  have  a  perfect  system  of  agriculture  made  up  of  them  all,  with- 
out systematic  arrangement. 

Another  advantage  of  such  a  book  is  that  the  general  reader  may  ob- 
tain the  first  principles  of  Chemistry,  Geology,  Botany  or  Meteorology, 
without  reading  a  large  amount  of  agricultural  science,  which,  to  him, 
may  be  of  little  use. 

The  author  is  aware  that  an  amount  of  matter  is  embodied  in  thi.s 
book  sufficient  to  make,  when  extended  and  amplified,  several  such 
volumes:  but  nearly  all  books  contain  much  by  way  of  explanation 
and  speculation,  that  could  well  be  omitted.  Some  things  may  be  found 
in  the  book  which  do  not  appear  to  have  any  direct  connection  with 
practical  agriculture;  but  a  little  observation  shows  that  the  science* 
discussed  all  have  such  a  connection  and  relation,  that  to  omit  any  prin- 
ciple would  destroy  the  harmony  of  the  whole  system. 

The  best  authorities  have  been  consulted, — so  that  whatever  may  be 
open  to  criticism  must  be  judged  by  their  testimony.  It  is  desirable 
that  the  agricultural  community,  for  whose  more  special  use  the  book 
is  designed,  may  be  disposed  to  favor  the  enterprise:  with  all  its  faults, 
therefore,  it  is  respectfully  committed  to  them — and  the  public; — with 
no  claims  except  to  their  forbearance,  and  no  means  of  propitiating 
their  favor,  beyond  its  own  merits. 

M.  M.  RODGERS 

Rochester.  August.  1848. 


AUTHORITIES  CONSULTED, 


KANE'S  CHEMISTRY, 

FOWNE'S 

SILLIMAN'S       " 

TURNER'S         " 

LIEBIG'S  AGRICULTURAL  " 

LYELL'S  GEOLOGY, 

HITCHCOCK'S  " 

COMSTOCK'S    " 

GRAY'S  BOTANY, 

WOOD'S      " 

EATON'S     " 

MULLER'S  ELEMENTS  OF  PHYSICS  AND  METEOROLOGY,. 

BOUSSINGAULT'S  METEOROLOGY, 

BRANDE'S  ENCYCLOPEDIA, 

LARDNER'S  LECTURES  ON  SCIENCE, 

ENCYCLOPEDIA  BRITTANICA, 

JOHNSTON'S  AGRICULTURAL  CHEMISTRY, 

BOUSSINGAULT'S  RURAL  ECONOMY, 

THAER'S  PRINCIPLES  OF  AGRICULTURE, 

PETZHOLDT'S  LECTURES  ON  AGRICULTURE, 

COLMAN'S  EUROPEAN  AGRICULTURE, 

GARDNER'S  FARMER'S  DICTIONARY, 

REPORT  OF  THE  REGENTS  OF  THE  UNIVERSITY  OF  N.  YORK, 

TRANSACTIONS  OF  THE  N,  Y,  STATE  AGRICULTURAL  SOCIETY, 


ACKNOWLEDGEMENTS. 


THE  Author  acknowledges  with  pleasure,  the  valuable  assist- 
ance of  several  scientific  and  practical  gentlemen,  to  whose 
names  he  is  permitted  to  refer — viz: 

CHESTER  DEWEY,  M.  D.,  Professor  Chemistry,  Geology,  &c- 
JOHN  J.  THOMAS,  Esq. 

L.  WlTHEREL,  A.  M. 

P.  BARRY,  Esq. 
L.  B.  LANGWORTHY,  Esq. 
AARON  ERICKSON,  Esq. 
D.  D.  T.  MOORE,  Esq. 

1C.,  GOODSELL,  Esq. 

Several  of  the  above  named  gentlemen  have  examined  por- 
tions of  the  manuscript  of  this  book,  and  made  such  sugges- 
tions and  corrections  as  they  thought  necessary. 

They  should  not,  however,  be  held  responsible  for  any  state- 
ment which  may  appear  to  be  erroneous,  or  for  the  selection* 
and  arrangement  of  the  topics  discussed.  M..  M.  E. 


INTRODUCTION. 


AGRICULTURE  is  doubtless  one  of  the  oldest,  most  honorable 
and  important  pursuits  among  civilized  nations.  Without  it 
the  food  of  man  must  have  been  limited  to  the  flesh  of  wild 
animals  and  the  spontaneous  productions  of  the  earth :  Com- 
merce could  not  exist  to  any  extent;  the  arts  and  sciences 
would  be  almost  unknown ;  and  society  could  not  advance  in 
improvement  beyond  a  refined  state  of  barbarism.  But  the 
culture  of  the  soil  enables  men  to  produce  more  of  the  neces- 
sary food  than  they  require,  so  that  a  part  only  are  required 
in  this  pursuit,  while  the  remainder  are  enabled  to  turn  their 
talents  and  ingenuity  to  some  other  useful  calling,  the  products 
or  services  of  which  are  given  to  the  agriculturist  in  exchange 
for  food. 

This  is  the  origin  of  the  division  of  labor,  which  is  at  the 
foundation  of  all  political  economy  and  true  governmental 
policy :  this  division  and  subdivision  of  labor  is  adopted  more 
extensively  the  more  a  nation  becomes  enlightened  and  pros- 
perous. Without  such  distribution  of  pursuits,  •  little  wealth 
could  be  accumulated  by  nations  or  individuals.  In  order 
that  every  man  should  be  independent  of  the  services  of  all 


12  INTRODUCTION. 

others,  he  must  manufacture  and  produce  every  thing  with 
his  own  hands  which  in  the  social  and  civilized  state  of  society, 
he  receives  from  them :  this  would  so  occupy  his  time  and 
talents  that  he  could  only  produce  the  bare  necessities  of  a 
primitive  life:  his  food  must  be  obtained  by  hunting,  fishing 
and  digging  roots, —  his  clothing,  the  skins  of  animals, — his 
shelter,  a  rude  hut,  and  his  only  beverage"  water. 

From  this  mode  of  living,  also,  the  earth  must  soon  contain 
more  inhabitants  than  could  subsist  on  its  spontaneous  food, 
and  part  must  die  of  starvation. 

The  art  of  agriculture  has  been  known  and  successfully 
practiced  by  some  of  the  oriental  nations  from  remote  ages. 

The  Chinese  appear  to  have  a  good  practical  knowledge  of 
soils,  and  have,  by  industry  and  skill  in  agriculture,  sustained 
a  population  of  an  almost  incredible  number:  and,  although 
they  are  supposed  to  be  but  little  removed  from  barbarism, 
they  are  said  to  excel  all  other  nations  in  the  amount  of  food 
which  they  produce  from  a  given  space  of  soil. 

That  the  ancient  Romans  had  an  amount  of  practical  know- 
ledge equal  to  most  nations  of  the  present  day,  is  evident  from 
the  following  passages  from  Virgil's  Georgics.  Thus  in  his 
first  Georgic  he  alludes  to  the  rotation  of  crops,  the  art  of 
manuring  and  burning  land. 

"  Yet  shall  thy  lands  through  easier  labor  rear 
Fresh  crops  by  changeful  produce  year  by  year, 
If  rich  manure  new  life  and  nurture  yield, 
And  ashes  renovate  the  exhausted  field. 
Thus  interchanging  harvests,  earth  repair; 
Nor  lands  unplowed,  meantime  no  profit  bear. 
Much  it  avails  to  burn  the  sterile  lands, 
And  stubble,  crackling  as  the  flame  expands; 
Whether  earth  gain  fresh  strength  or  richer  food, 
Or  noxious  moisture,  forced  by  fire  exude; 
Whether  it  draw  through  many  an  opening  vein, 
Juice  to  fresh  plants  that  clothe  anew  the  plain, 
Or  brace  the  pores,  that  pervious  to  the  day, 
Felt  the  prone  sun's  intolerable  ray, 
To  piercing  showers  the  expanded  fissure  close, 
And  the  chill  north  that  blisters  as  it  blows." 


INTRODUCTION.  13 

Again  in  the  second  Georgic  we  have  evidence  that  they 
studied  the  nature  of,  and  adapted  various  crops  to  different 
qualities  of  soils. 

"  Now  learn  the  soils,  the  nature  of  each  field, 

What  fruits  their  varying  strength  and  virtue  yield; 
Know  first,  the  ungenial  hill  and  barren  land, 
Where  sterile  beds  of  hungry  clay  expand, 
And  thorns  and  flints  deface  the  rugged  earth, 
Demand  the  long  lived  plants  palladian  birth." 

In  the  other  three  Georgics  we  learn  that  the  Romans 
understood  horticulture,  gardening,  the  management  of  do- 
mestic animals  and  bees, — and  the  extermination  of  noxious 
weeds  and  insects.  Limited  as  were  their  mechanical  means, 
and  their  knowledge  of  chemistry,  geology  and  botany, — still 
their  skill  and  success  would  seem  to  exceed  that  of  agricultu- 
rists of  the  present  day ;  and  in  fact  we  may  almost  believe 
that  the  practical  knowledge  of  farming  has  retrograded  since 
that  time.  If  this  is  the  case,  it  cannot  be  because  science 
has  been  detrimental  to  modern  practice, — but  is  rather  owing 
to  their  close  observation  of  nature,  and  their  attentive  indus- 
try. It  is  no  argument  against  the  art  of  culture  being 
conducted  on  scientific  principles :  the  success  of  practical  men 
is  due  to  the  discovery  and  carrying  out  of  these  principles, 
although  they  may  be  ignorant  of  them,  and  may  not  recog- 
nize them  as  such.  The  idea  that  the  farmer  requires  nothing 
but  practice  and  experience  to  ensure  success,  is  as  erroneous 
as  to  suppose  the  school  teacher  requires  no  knowledge  of 
arithmetic  or  grammar.  Not  a  blade  of  grass  can  be  made  to 
grow  without  perfect  conformity  to  the  laws  of  nature, —  and 
still  the  farmer  arrogates  to  himself  the  credit  of  success  in  an 
operation,  the  philosophy  of  which  he  neither  does,  nor  desires 
to  understand. 

The  failures  of  practical  men  in  attempting  to  apply  some 
new  principle,  are  owing  to  want  of  knowledge  and  skill  in 
combining  science  with  practice, — and  not  to  any  discrepancy 

2 


14  INTRODUCTION. 

in  facts.  It  must  be  admitted  that  many  of  the  processes  of 
successful  farming  are  not  yet  explained, — and  many  things, 
true  in  theory,  are  not,  as  yet,  demonstrated  in  practice,  but 
this  does  not  justify  the  conclusion  that  nature  is  not  entirely 
consistent  with  herself.  Men  have  been  too  much  disposed  to 
consider  certain  phenomena  as  "  mysterious  and  past  finding 
out,"  and  thus  have  ended  their  investigations. 

But  the  time  has  arrived  when  the  application  of  science  is 
the  only  means  of  any  great  success  in  agriculture ;  and  those 
who  reject  this  light  must  be  content  to  plod  their  way 
through  life  like  one  groping  in  darkness, — be  considered  as 
wanting  in  intelligence  and  enterprize, — to  accomplish  but 
little  and  barely  subsist, — while  the  scientific  farmer  reaps 
abundant  harvests.  However  strong  the  prejudice  may  be 
against  what  is  absurdly  called  "book  farming," — the  old 
empyrical  system  cannot,  in  a  country  where  the  population  is 
dense,  the  soil  becoming  exhausted,  and  manures  scarce, 
maintain  a  successful  competition  with  one  which  is  conducted 
upon  scientific  principles. 

No  art  or  profession  presents  more  points  of  contact  with  the 
various  branches  of  natural  science  than  that  of  agriculture ; 
and  in  no  pursuit  is  education  regarded  as  of  less  importance. 
While  in  all  the  learned  professions  and  many  mechanical 
arts,  education  is  considered  indispensible, — the  farmer  whose 
knowledge  consists  of  reading,  writing,  and  a  few  empyrical 
dogmas  of  his  ancestors,  is  supposed  to  be  abundantly  quali- 
fied for  his  calling.  Trained  and  educated  in  all  the  old  and 
established  practices  of  his  fathers,  he  is  sceptical  upon  all 
that  is  written,  and  slow  to  adopt  any  new  improvement  in 
practice. 

An  ancient  philosopher  being  asked  what  things  were  most 
propei  for  boys  to  learn,  replied, — "  Those  things  which  they 
intend  to  practice  when  they  become  men."  Now  inasmuch 
as  agriculture  involves  the  same  branches  of  knowledge  as 


INTRODUCTION.  15 

most  other  arts  and  professions,  it  follows  of  necessity  that  the 
farmer  requires  the  same  education  and  discipline  of  mind  as 
those  do  who  practice  law,  medicine,  engineering,  and  the 
mechanical  arts. 

Agriculture  should  not  be  looked  upon  as  the  end  of  life, — 
but  only  as  a  means  of  securing  the  necessary  food  for  subsis- 
tence: this,  as  well  as  all  other  pursuits,  should  be  adopted 
with  the  view  of  enabling  men  not  only  to  improve  and 
beautify  the  earth,  but  to  cultivate  the  moral,  intellectual  and 
social  powers,  and  to  fulfil  according  to  their  capacity,  their 
proper  station  among  their  fellow  men.  It  should  not  tend  to 
make  men  mere  machines,  who  toil  for  the  sole  purpose  of 
gratifying  grovelling  and  depraved  appetites ;  but  it  should 
elevate  and  refine  to  the  highest  degree  of  perfection,  all  the 
better  faculties  of  our  nature. 

A  large  part  of  the  farming  community  already  recognize 
the  utility  of  the  natural  sciences  in  the  cultivation  of  the  soil. 

Some  elementary  books  have  been  written  which  have 
been  favorably  received  by  the  farming  public.  Among 
the  natural  sciences,  Geology  has  received  more  attention  than 
any  other  among  this  class  of  men.  The  connection  of  this 
science  with  agriculture  is  so  apparent  to  every  one  who 
learns  but  the  rudiments  of  it,  that  it  needs  only  to  be  intro- 
duced, (in  treatises  which  are  plain  and  well  arranged,)  to  be 
studied  and  applied  in  practice.  It  teaches  the  origin  and 
nature  of  all  the  various  soils  and  rocks,  and  all  great  physical 
changes  which  are  taking  place  from  natural  causes  on  the 
earth,  and  beneath  its  surface. 

Botany  is  also  of  much  importance:  and  indeed  the  agricul- 
turist and  horticulturist  are  the  only  persons  to  whom  the 
study  and  practical  application  of  its  principles  are  indispen- 
fitble.  It  teaches  the  characters,  habits  and  localities  of  nearly 
one  hundred  thousand  different  species  of  plants;  it  treats 


T.6  INTRODUCTION. 

also   of  their   physiology,  and   explains   many   of  the   most 
interesting  processes  of  vegetation. 

Chemistry  is  the  key  which  unlocks  the  great  laboratory  of 
nature,  and  shows  us  how  she  performs  her  complicated 
processes,  and  produces  all  her  wonderful  phenomena. 

Meteorology  investigates  all  the  facts  and  phenomena  per- 
taining to  weather,  climate,  seasons,  temperature,  storms,  lati- 
tude, altitude,  winds,  &c. 

Zoology  treats  of  the  habits,  localities,  depredations  and 
uses  of  all  the  objects  of  the  animal  kingdom.  Comparative 
anatomy  and  physiology  constitute  a  branch  of  zoology  which 
treats  of  the  form,  structure,  functions,  differences  and  pecu- 
liarities of  all  the  organs  of  animal  bodies.  It  is  the -basis  of 
all  knowledge  relative  to  breeding,  rearing,  feeding,  and 
curing  the  diseases  of  animals. 

Natural  Philosophy  treats  of  the  properties  and  dynamic 
forces  of  light,  air,  water,  and  the  mechanical  powers,  and 
their  application  to  machinery  and  other  practical  purposes  of 
life.  Besides  these,  many  other  branches  of  knowledge  are 
indispensible  to  the  education  of  the  accomplished  agricultu- 
rist. The  study  of  astronomy,  geography,  architecture,  politi- 
cal economy,  algebra,  geometry,  —  a  knowledge  of  the  lan- 
guages, general  literature,  and  the  fine  arts  to  some  extent, — 
and  in  fact  we  might  say,  a  complete  collegiate  course,  belongs 
as  much  to  the  farmer  as  to  the  professional  man. 

But  the  means  by  which  this  amount  of  preparatory  educa- 
tion is  to  be  attained  by  farmers'  sons,  are  not  yet  provided. 
Various  plans  for  agricultural  schools  have  been  proposed, 
none  of  which  have  been  successful  in  this  country.  Where 
such  schools  have  been  established  and  endowed  with  compe- 
tent instructors,  library  and  apparatus,  the  number  of  pupils 
have  been  a  mere  fraction  of  the  young  men  who  were 
destined  for  agricultural  pursuits.  While  a  few  are  ambitious 
of  high  attainments,  the  great  mass  are  indifferent,  or  preju- 


INTRODUCTION.  17 

diced  against  what  they  suppose  to  be  only  an  innovation.  In 
this  way  the  schools  fail  for  want  of  patronage,  and  young 
are  deprived  of  their  education  for  want  of  schools. 

But  if  we  are  not  yet  prepared  to  sustain  agricultural 
schools,  some  other  plan  may  be  available.  The  teachers  of 
common  schools  may  be  educated  in  scientific  agriculture,  so 
as  to  be  able  to  instruct  all  such  pupils  as  are  designed  for 
this  pursuit,  in  at  least  the  elements  of  the  most  necessary 
branches.  In  this  way  the  germs  of  science  will  be  planted 
and  a  taste  excited,  which  will  lead  ultimately  to  a  thorough 
and  systematic  course  of  study. 

This  plan,  though  limited  and  imperfect  in  its  operation,  has 
the  ad/antage  of  giving  to  boys,  early  impressions,  and  a 
preference  for  those  studies,  which,  if  proper  books  are  acces- 
sible, may  be  pursued  in  connection  with  practice  in  after  life. 
A  plan  has  been  proposed  for  securing  the  agricultural  educa- 
tion of  teachers,  which  is  to  establish  a  professorship  of  agri- 
cultural science  in  the  State  Normal  School.  By  this  means 
teachers  could  be  educated,  who  would  be  competent  to  teach 
the  science  to  the  extent  required  in  the  schools  of  farming 
communities. 

Every  farm  should  be  considered  a  chemical  laboratory, 
and  every  farmer  a  practical  chemist  and  philosopher :  farming 
would  then  be  honorable  and  lucrative.  Education  would 
give  to  the  cultivator  of  the  soil  that  dignified  confidence  and 
polish  which  he  has  a  right  to  possess, — and  which  he  now  " 
too  often  ridicules  or  envies  in  men  in  other  pursuits.  No- 
reason  exists  why  rural  pursuits  should  alienate  their  votaries 
from  the  rest  of  mankind,  and  give  rise  to  those  jealousies  and 
suspicions  with  which  they  look  upon  men  of  other  occupa- 
tions, or  fill  the  mind  with  that  dogged  arrogance  which  is 

always  the  offspring  of  ignorance. 

' 

The  profits  of  productive  farming  would,  when  conducted 
2* 


IO  INTRODUCTION. 

scientifically,  enable  the  farmer  to  accumulate  wealth,  and 
enjoy  all  the  comforts  and  luxuries  of  refined  life.  Every 
community  could  be  made  up  of  the  best  society, — every 
family  could  have  its  fine  library  and  its  accomplished  sons 
and  daughters:  farmers'  sons  need  not  leave  the  favorite 
pursuit  of  their  fathers,  and  go  into  the  learned  professions, 
from  the  erroneous  conclusion  that  they  were  more  honorable 
or  profitable.  Farmers'  daughters  need  not  despise  the 
delightful  and  healthful  employments  of  the  dairy,  the 
kitchen,  or  the  loom, — and  seek  elevation  in  the  miserable 
pursuits  and  fashions  of  the  city. 

Nothing  conduces  more  to  the  elevation  and  refinement  of 
the  mind  than  the  study  of  nature ;  the  man  who  holds  fre- 
quent communion  with  nature,  and  studies  and  obeys  her 
laws,  is  always  made  a  better  and  happier  man. 

The  more  we  explore  the  mysteries  of  nature,  the  more  are 
we  humbled  with  the  reflection,  that  to  our  finite  view,  only  a 
small  part  of  her  works  are  comprehensible.  And  when,  after 
years  of  patient  toil,  we  fancy  we  have  learned  most  of  her 
laws,  we  still  find  the  great  Author  has  only  opened  to  our 
view  new  vistas  to  more  extensive  and  unexplored  fields  of 
knowledge. 

"  Nature  is  always  perfect  and  unvarying,  but  man's 
knowledge  is  progressive ;  consequently  in  every  advance  he 
arrives  nearer  the  truth,  yet  as  far  from  knowing  all  nature 
and  her  laws  as  he  is  from  infinity.  Exact  knowledge  consists 
in  those  things  which  can  be  seen  and  demonstrated, — while 
in  all  knowledge  of  inference  there  is  progression.  Opinions, 
which  are  often  the  result  of  imperfect  knowledge,  are  liable 
to  change,  and  the  mind  is  never  advanced  by  adopting  the 
opinions  of  others;  for  by  that  means  man  is  never  made  a 
thinking  being,  but  rests  upon  authority  In  all  sciences,  the 
acquisition  of  new  truths  exhibits  in  a  new  light,  the  beautiful 
and  harmonious  operation  of  the  laws  of  nature." 


INTRODUCTION.  19 

Besides  the  benefit  of  mental  discipline  derived  from  the 
study  of  nature,  for  which  agriculture  opens  as  wide  a  field 
as  any  other  pursuit,  the  charms  of  rural  life  are  unalloyed 
by  the  reflection  of  ill-gotten  gain,  and  uncontaminated  by 
immoral  influences.  The  farmer  has  no  occasion  to  review 
with  remorse,  a  life  of  injustice  to  his  fellow  men,  or  mourn 
the  loss  of  fortunes  accumulated  by  an  occupation  almost 
necessarily  dishonest. — The  lawyer  looks  upon  his  briefs  pre- 
pared for  unjust  causes,  the  physician  upon  the  emaciated 
forms  of  his  patients,  and  the  speculator  upon  the  wealth 
amassed  from  the  ruined  fortunes  of  others,  with  the  humilia- 
ting consciousness  that  they  have  not,  in  all  cases,  returned  an 
equivalent  for  what  they  have  received.  But  the  cultivator 
of  the  soil  may  pursue  his  calling  with  the  cheering  reflection, 
that  an  all  bounteous  Providence  has  rewarded  his  efforts,  and 
through  him  bestowed  means  of  happiness  upon  his  fellow 
men. 

The  reminiscenses  of  rural  life  and  scenes  are  always 
pleasant:  who  would  not  wish  to  return  to  the  bounding  and 
joyous  days  of  youth,  which  were  spent  among  woodland 
scenes,  green  fields,  along  the  river's  shore,  on  the  sunny  hill's 
side,  or  in  the  silence  of  the  cool  ravine,  where  every  object 
lent  enchantment  to  the  scene,  afforded  pleasure  without 
alloy,  and  prepared  the  mind  for  the  admiration  of  nature  and 
study  of  her  laws  in  maturer  years.  What  haunts  so  sacred, 
what  objects  so  linked  to  our  affections,  as  those  associated 
with  rural  life  in  childhood.  Who  that  appreciates  the 
quietude  and  smiling  plenty,  the  balmy  air  and  variegated 
landscape  of  the  country, — would  not  prefer  it  to  the  crowded 
noisy  streets,  the  pestiferous  atmosphere  and  demoralizing 
influences  of  the  city.  It  is  in  the  country  alone  that  man 
enjoys  the  beauties  of  nature,  as  she  spreads  them  out  before 
him  in  all  their  wild  luxuriance,  or  as  she  patiently  smiles 
beneath  the  improving  hand  of  cultivation. 


20  INTRODUCTION. 

Agriculture  is  an  honorable,  a  delightful  and  a  glorious 
pursuit:  the  first  man  who  lived  on  earth  was  an  agriculturist, 
—-and  agriculture  must  exist  till  the  last  man  leaves  it. 

But  all  labor  is  honorable:  the  GREAT  FIRST  CAUSE 
works,  —  nature  works,  —  and  every  man  who  enjoys  her 
fruits,  ought  to  hold  it  honorable  to  work.  When  shall  the 
glorious  time  dawn,  that  intelligence  and  true  philanthropy 
shall  annihilate  the  selfish  distinction  which  pride  has  made 
between  labour  and  idleness?  May  that  auspicious  day  soon 
arrive  when  the  worthless  distinctions  between  mental  and 
physical  labour  shall  cease  to  exist,  which  separates  man  from 
his  fellow  man, — and  all  the  tenants  of  earth  meet  as  equal 
sovreigns  of  our  common  inheritance. 


NATURAL    SCIENCE. 


NATURAL  SCIENCE  embraces  all  the  objects  of  the  material 
creation,  from  the  minutest  insect,  plant  or  particle  of  dust,  to 
the  most  vast  of  the  celestial  spheres.  This  great  field  of 
knowledge  is  divided  into  Natural  Philosophy  and  Natural 
History.  Natural  Philosophy  elucidates  the  laws  which  gov- 
ern the  phenomena  of  the  material  world, — and  is  divided 
into  Chemistry  and  Physics.  Chemistry  treats  of  phenomena 
which  depend  upon  a  change  in  the  constitution  of  bodies: 
Physics  treats  of  the  dynamical  properties  and  phenomena  of 
bodies,  which  do  not  depend  on  a  change  in  constitution  or 
elements. 

Natural  History  treats  of  the  character  and  properties  of 
individual  objects :  these  are  divided  into  three  great  natural 
groups  called  kingdoms, — viz.  the  animal,  the  vegetable  and 
the  mineral  kingdom.  Natural  objects  are  distinguished  also 
into  two  great  classes  termed  animate- organic  and  inanimate- 
inorganic.  All  the  individuals  of  each  of  the  primary  divi- 
sions, are  again  divided  or  grouped  into  Classes,  Orders,  Ge- 
nera and  Species. 

The  dividing  line  between  organic  life  and  inanimate  mat- 
ter, is  not  well  defined;  between  the  lowest  form  of  organic 
life  and  the  most  perfect  and  symmetrical  crystal  of  the  mine- 


22  NATURAL   SCIENCE. 

ral  kingdom,  however,  the  distance  must  be  almost  immeasura- 
bly great.  Passive  motion  or  change,  is  the  peculiar  attribute 
of  inorganic  matter:  it  can  neither  enjoy  life,  nor  be  subject 
to  death  :  but  life  and  organization  are  inseparable, — to  this 
combination,  birth  and  death,  are  the  necessary  and  invaria- 
ble terms  of  existence. 


PART   I. 


CHEMISTRY 


CHAPTER  I. 

THE  science  of  Chemistry  has  for  its  object  the  investigation 
of  the  properties  of  all  elementary  and  compound  substances, 
their  relations  and  combinations,  the  agencies  by  which  their 
changes  are  effected,  and  the  laws  which  govern  them.  The 
basis  on  which  this  science  rests,  is  facts  and  experiment;  and 
as  it  is  purely  a  demonstrative  physical  science,  no  hypotheti- 
cal or  speculative  views  can  be  practically  made  of  any  ser- 
vice to  its  advancement  and  application. 

Every  change  which  takes  place  in  the  elementary  consti- 
tution of  matter  in  the  universe,  whether  effected  by  natural 
causes  or  by  the  operations  of  art,  involves  a  fixed  chemical 
law,  and  is  due  to  chemical  action. 

Chemistry  consists  of  two  distinct  branches,  viz.  Analysis 
and  Synthesis.  Analysis  consists  in  decomposing  a  compound 
body  and  separating  its  elements.  Synthesis  consists  in  uni- 
ting simple  bodies  so  as  to  form  a  compound  substance.  The 
forces  which  preside  over  and  cause  all  chemical  changes,  are, 
attraction,  light,  caloric,  electricity  and  magnetism.  The  rela- 
tive importance  of  these  several  forces  cannot  be  exactly  esti- 
mated in  the  present  state  of  the  science :  the  question  as  to 


24  SCIENTIFIC    AGRICULTURE. 

their  individual  nature,  or  identity  with  electricity,  remains 
unsettled. 

The  science  of  chemistry,  which  has  achieved  greater  tri- 
umphs over  matter,  and  conferred  more  practical  knowledge 
of  nature  upon  civilized  man  than  all  other  sciences  com- 
bined,— has  gradually  grown  out  of  the  superstitious  art  of 
Alchemy. 

Modern  chemistry,  instead  of  alluring  its  votaries  into  a 
fruitless  search  after  the  "philosopher's  stone,"  crowns  their 
investigations  with  results  which  tend  to  the  advancement  of 
civilization  and  the  increase  of  human  comforts  and  happi- 
ness. Its  objects  are  not  limited  to  the  study  of  abstract  laws 
alone ; — but  also  to  the  improvement  of  the  useful  arts,  the 
cure  of  disease,  the  production  and  preparation  of  food,  the 
study  of  the  laws  of  organic  life,  and  finally  to  every  thing- 
affecting  our  physical  relations  to  the  material  universe. 


PROPERTIES  OF  BODIES. 

CAPILLARITY. 

Capillarity  is  the  force  by  which  small  tubes  and  porous 
substances  absorb  and  raise  fluids  above  the  surface  of  that  in 
which  they  are  immersed.  This  force  depends  upon  the  cohe- 
sion of  the  molecules,  or  ultimate  atoms  of  the  fluid  for  each 
other,  and  the  attraction  of  the  solid  body  for  those  of  the 
fluid.  If  we  dip  the  end  of  a  small  tube  open  at  both  ex- 
tremities, into  a  fluid,  it  will  be  observed  to  rise  slowly  above 
the  surface  of  the  surrounding  mass :  if  one  corner  of  a  sponge 
be  dipped  into  water  and  allowed  to  remain,  it  will  by  virtue 
of  its  capillarity  in  a  little  time  be  saturated ;  the  water  hav- 
ing been  raised  by  this  force  against  the  antagonizing  force  of 
gravity. 


CHEMISTRY.  25 

COHESION. 

Cohesion  is  the  force  by  which  the  particles  of  a  homogene- 
ous body  are  held  together  and  resist  separation.  Caloric  is 
the  opposing  or  antagonizing  force  of  cohesion.  "  The  three 
different  forms  which  matter  assumes, — viz.  solid,  liquid  and 
gaseous, — are  determined  by  the  degree  of  the  cohesive  force 
existing  among  the  elementary  particles."  This  force  is  great- 
est in  solids,  less  in  fluids,  and  least  in  gases.  In  gases  this 
force  is  negative  or  absent,  the  particles  having  a  tendency  to 
repel  each  other.  The  globular  form  of  the  drops  of  liquids 
depends  upon  this  force. 

It  is  easy  to  conceive  that  if  cohesion  were  to  be  suspended, 
all  solids  as  well  as  fluids  would  assume  the  gaseous  form ; 
the  repulsive  tendency  beingt  henu  ncontrolled.  This  can  be 
effected  to  a  certain  extent  by  means  of  heat :  heat  overcomes 
the  cohesive  power  of  solids  and  changes  them  to  liquids :  but 
when  the  heat  is  removed,  they  are  again  changed  to  solids  by 
cohesion, — as  in  the  case  of  melted  iron  :  bodies  naturally 
liquid,  as  water  and  mercury,  are  volatilized  by  heat,  and  as- 
sume the  gaseous  form.  The  cohesive  force  acts  at  insensible 
distances. 

DIVISIBILITY. 

Matter  is  capable  of  being  divided  into  inconceivably  small 
particles.  We  have,  however,  no  means  of  determining  the 
question  of  its  infinite  divisibility.  We  can  easily  imagine  that 
the  minutest  particle  which  can  be  produced  by  mechanical 
means,  must  still  have  extension,  form  and  weight,  and  would 
be  divisible,  (had  we  instruments  sufficiently  delicate,)  into 
other  particles,  and  these  again  into  others,  and  so  on  until 
they  totally  disappeared  from  the  limit  of  our  conceptions. 
But  we  cannot  by  any  process  whatever  annihilate  or  destroy 
the  least  particle  of  matter. 

The  particles  of  hydrogen  gas,  which  is  itself  fourteen  times 
lighter  than  common  air,  would,  individually  present  an  idea 

3 


26  SCIENTIFIC  AGRICULTURE. 

almost  inconceivable.  And  still  this  gas  is  material,  and  must 
be  made  up  of  an  aggregate  of  particles.  A  single  grain  of 
gold  used  in  gilding  silver  wire,  is  made  to  cover  a  surface  of 
1400  square  inches,  and  still  the  gold  upon  the  millionth  of  a 
square  inch  when  examined  by  the  microscope,  is  distinctly 
visible.  A  square  inch  of  gold  leaf  may  be  divided  into  one 
billion  and  four  hundred  millions  of  particles,  and  still  retain 
all  the  characters  and  color  of  a  large  mass. 

Chemical  action  may  be  supposed  to  carry  the  process  of 
division  to  a  much  higher  attenuation  than  mechanical  means. 
A  single  drop  of  solution  of  indigo  colors  1000  cubic  inches  of 
water,  and  yet  this  coloring  matter  is  an  aggregate  of  distinct 
particles.  The  fineness  of  particles  has  an  important  effect 
on  the  chemical  action  of  one  body  upon  another.  Perhaps  a 
more  definite  idea  may  be  given  by  the  following  example. 
The  author  had  the  pleasure  of  examining  with  Professor 
Dewey's  improved  microscope,  some  fossil  infusoria,  which 
were  so  small  that  they  appeared  like  perfectly  impalpable 
powder,  and  not  the  least  gritty  between  the  teeth.  These 
minute  particles  of  dust  when  subject  to  the  greatest  magni- 
fying power  of  the  instrument,  proved  to  be  the  shells  of  in- 
fusoria resembling  in  shape  the  sow-lug  and  trilobite,  and  ap- 
parently from  three  to  four  inches  in  length  and  one  inch  in 
width.  And  still,  minute  as  they  were,  they  must  have  had 
when  living,  all  the  organs  and  machinery  of  animals  of  large 
size. 

GRAVITY. 

The  term  gravity,  in  natural  philosophy,  signifies  weight :  it 
is  that  force  or  attraction  in  nature  which  causes  all  bodies  to 
move  towards  the  earth  when  not  prevented  by  some  other 
force.  The  gravitating  force  of  a  body  is  in  proportion  to  the 
quantity  of  matter  which  it  contains.  The  force  of  gravity  in- 
creases in  falling  bodies,  in  proportion  as  they  approach  the 
earth.  Bodies  of  the  same  bulk,  do  not  always  possess  the 


CHEMISTRY.  27 

same  gravity  or  weight,  owing  to  difference  in  density :  thus 
lead  weighs  about  twelve  times  as  much  as  cork,  bulk  for 
bulk, — that  is,  it  contains  twelve  times  as  much  matter, — and 
hence  it  has  twelve  times  the  gravitating  force. 

What  this  gravitating  force  is,  has  not  been  determined ;  all 
we  know  in  relation  to  it  is,  its  effects.  Specific  gravity,  de- 
notes the  weight  of  any  body,  compared  with  some  other  body 
of  equal  bulk,  which  is  taken  as  a  standard  and  is  reckoned  at 
unity.  Water  is  taken  as  the  standard  of  specific  gravity  for 
solids  and  fluids,  while  atmospheric  ah-  is  the  standard  from 
which  the  weight  of  the  gases  is  estimated. 

DENSITY. 

By  density,  is  understood,  the  compactness  of  bodies,  or  the 
number  of  ultimate  particles  contained  in  a  given  bulk :  bodies 
which  contain  the  most  particles  are  most  dense, — that  is,  their 
particles  are  in  the  closest  proximity  to  each  other.  Rarity,  or 
porosity  is  opposed  to  density.  Density  does  not  depend  upon 
the  peculiar  kind  of  matter  of  which  a  body  is  composed,  but 
only  upon  the  proximity  of  its  particles.  This  is  apparent, 
from  the  fact  that  the  lava  ejected  from  volcanoes,  if  cooled 
on  the  surface  of  the  earth,  produces  a  stone  sufficiently  light 
and  porous  to  float  upon  water, — while  if  cooled  under  great 
pressure  at  a  distance  below  the  surface,  it  forms  a  dense 
heavy  rock  like  granite. 

ELASTICITY. 

Elasticity  is  the  property  in  bodies,  which  causes  them  to 
resume  their  original  form  and  bulk,  after  being  bent,  com- 
pressed or  condensed.  Most  solid  and  hard  bodies  possess 
this  quality  in  some  degree  :  glass,  ice,  ivory,  <fec.  are  elastic 
solids :  india-rubber  is  an  exceedingly  elastic  body, — while  wet 
clay  is  entirely  destitute  of  this  property.  The  gases  are  far 
the  most  elastic  of  all  bodies. 


23  SCIENTIFIC  AGRICULTURE. 

TENACITY. 

By  tenacity,  we  understand  the  degree  of  force  or  cohesion 
with  which  the  particles  of  a  body  are  held  together, — in  other 
words  tenacity  means  toughness.  Some  substances,  as  some 
of  the  metals,  are  extremely  tenacious,  while  others  want  this 
quality  almost  totally.  The  tenacity  of  the  metals  varies  great- 
ly,— cast  steel  being  the  most  tenacious  of  them  all,  while  lead 
is  the  least  so.  The  tenacity  of  the  woods  varies  as  does  also 
that  of  soils :  clay  soil  is  tenacious,  while  sand  soil  is  destitute 
of  this  property. 

CHEMICAL  ATTRACTION,  OR  AFFINITY. 

This  is  a  peculiar  power  in  bodies,  which  disposes  them  to 
unite  with  other  bodies  and  form  compounds.  It  is  the  power 
by  which  chemical  phenomena  are  produced:  it  is  different 
from  cohesion  and  all  other  forces  in  nature:  it  acts  with 
various  degrees  of  energy  in  different  elementary  bodies, — 
showing  a  preference  for  some,  and  refusing  to  act  on  others 
at  all.  Chemical  affinity  is  influenced  by  many  other  agents, 
as  heat,  electricity,  gravity,  cohesion,  moisture,  elasticity  and 
light.  An  affinity  originally  weak,  may  by  some  of  these 
agencies  be  made  strong,  while  an  affinity  originally  strong 
may  be  rendered  weak  or,  destroyed  altogether. 

When  common  salt  is  thrown  in  water,  it  unites  with  it, 
(dissolves,)  by  means  of  a  weak  affinity  or  chemical  attraction, 
— but  if  oil  be  thrown  into  water,  it  does  not  unite  with  it, 
because  it  has  no  affinity  for  it  Some  substances  unite  in  all 
proportions,  as,  for  example,  vinegar  and  water;  while  others 
unite  only  in  definite  and  fixed  proportions,  as  sulphuric  acid 
and  lime,  &c.  When  two  substances  of  opposite  natures  are 
brought  together,  as,  vinegar  and  pearlash,  they  readily  unite, 
by  means  of  simple  affinity,  and  form  a  third  substance  dif- 
ferent from  either  of  the  other  two.  If  now  a  third  substance 
be  added,  which  has  a  stronger  affinity  for  one  of  these  two 
than  they  have  for  each  other,  the  two  first  separate,  or  are 


CHEMISTRY.  29 

decomposed,  and  one  of  them  goes  to  unite  with  the  new 
substance,  and  form  a  compound,  by  means  of  elective  affinity. 
Two  bodies  which  have  no  affinity  for  each  other,  may 
sometimes  be  made  to  unite  by  means  of  a  third :  thus,  oil  and 
water  will  not  unite  alone, — but  by  the  medium  of  the  alkali 
potash,  which  has  an  affinity  for  both,  they  unite  and  form  the 
well  known  compound,  soap.*  Chemical  union  is  usually 
attended  with  the  evolution  of  heat.  Some  substances  unite 
without  any  apparent  action,  while  others  have  an  affinity  so 
strong  that  union  takes  place  with  an  explosion.  Chemical 
affinity  manifests  itself  iu  a  more  complex  form  under  the 
name  of  double  elective  affinity. 

When  nitrate  of  ammonia  and  carbonate  of  potash  are 
mixed  together  in  solution,  a  double  decomposition  and  reunion, 
take  place :  the  potash  leaves  the  carbonic  acid  to  go  to  the 
nitric  acid,  and  the  nitric  acid  leaves  the  ammonia  to  go  to 
the  potash, — the  carbonic  acid  and  ammonia,  finding  them- 
selves deserted  and  alone,  unite  and  form  carbonate  of  ammo- 
nia. Thus  nitrate  of  ammonia  and  carbonate  of  potash  are 
decomposed,  and  nitrate  of  potash  and  carbonate  of  ammonia 
formed.  This  may  be  more  clearly  shown  by  arranging  the 
four  elements  thus : 

Nitrate  of  (  1.  Nitric  Acid.     3.  Potash.  )  Carbonate 

Ammonia.  (  2?  Ammonia.        4.  Carbonic  Acid.  )  of  Potash. 

This  change  of  elements  took  place  because  a  stronger 
affinity  existed  between  1  and  3,  than  between  1  and  2, — and 
a  stronger  affinity  existed  between  2  and  4,  than  between  3 
and  4.  These  compounds  might  again  be  decomposed  by 
others,  having  affinities  sufficiently  powerful  to  overcome  that 
which  holds  them  together.  In  order  that  bodies  may  be 

*  This  example  is  taken  from  Comstock's  Chemistry  on  account  of 
its  plainness;  but  is  nevertheless  not  strictly  true,  as  the  idea  of  an 
intermediate  substance  is  now  abandoned  by  chemists.  The  truth  is, 
that  the  alkali  and  oil  unite  and  form  soap,  which  it  itself  dissolved  in 
the  water. 


30  SCIENTIFIC   AGRICULTURE. 

united  by  affinity,  they  must  possess  different  chemical  proper- 
ties: thus  acids  and  alkalies  are  chemically  opposed,  and  are 
consequently  drawn  together,  while  they  rarely,  if  ever,  unite 
with  each  other.  "We  might  [says  Dr.  Fownes]  define 
chemical  affinity  to  be  a  force  by  which  new  substances  are 
generated." 

LAWS  OF  COMBINATION. 

The  elements  of  chemical  compounds  are  -generally  limited 
to  fixed  and  invariable  proportions  on  both  sides.  It  is  this 
constancy  of  proportions  alone,  which  gives  to  chemistry  its 
title  to  the  character  of  an  exact  science ;  for  had  all  bodies 
the  property  of  combining  in  every  possible  proportion  under 
every  variety  of  circumstances,  no  definite  or  certain  knowledge 
could  be  obtained  in  relation  to  the  constitution,  properties  or 
chemical  uses  of  bodies:  experiments  would  give  results  so 
different  and  variable,  at  different  times,  and  under  various 
circumstances,  that  the  votaries  of  this  sublime  and  useful 
science  would  long  since  have  abandoned  it  in  despair. 

The  elements  of  a  given  chemical  compound  are  always  in 
the  same  proportions :  thus,  green  oxide  of  iron  is  composed 
of  27  parts,  by  weight,  of  iron,  and  8  parts  of  oxygen:  com- 
mon salt  is  a  compound  of  23  parts  sodium  and  35  parts 
chlorine;  and  these  are  the  smallest  proportions  in  which 
those  elements  can  be  made  to  unite.  When  two  elements 
unite  in  more  than  one  proportion  on  either  side,  the  additional 
proportions  are  just  double,  triple,  quadruple,  &c.,  or  1  to  $ — 
that  is  2  to  3, — 3  to  5, — the  amount  of  the  first :  that  is,  they 
increase  in  exact  multiple  proportions.  To  illustrate  this 
principle  we  may  allude  to  the  five  compounds  of  oxygen  and 
nitrogen. 

Protoxide  of  nitrogen  consists  of — 

Nitrogen,     14.06  Oxygen,  8 

Deutoxide                   "           14.06                   "  16 

Hyponitrous  acid       "            14.06                   "  24 

Nitrous  add              «            14.06                   «  32 

Nitric  acid                «           14.06                  «  40 


CHEMISTRY.  31 

It  will  be  seen  that  while  the  nitrogen  remains  the  same,  the 
oxygen  increases  by  multiples  of  8,  which  is  its  equivalent 
number.  The  nitrogen,  although  willing  to  unite  with  several 
whole  proportions  of  oxygen,  would  reject  a  quarter  or  half 
of  an  equivalent,  and  not  unite  with  it :  so,  in  the  preparation 
of  any  compound,  if  an  excess  of  either  element  be  used,  it  is 
not  combined,  but  left  alone  in  its  original  state. 

The  equivalent  or  combining  number  of  a  body  is  that  which 
represents  the  smallest  in  which  it  is  known  to  combine  with 
other  bodies.  The  representative  number  of  a  compound,  is 
the  sum  of  the  combining  equivalents  of  its  components.  Com- 
bining proportions  are  reckoned  by  weight  and  by  volume ;  in 
these  two  estimations  of  course  different  equivalent  numbers 
are  used. 


CHAPTER  II. 


LIGHT. 


IN  order  to  understand  the  relations  of  light  to  vegetation,  a 
short  description  of  its  properties  is  necessary.  There  are  two 
theories  respecting  the  nature  of  light :  one  supposes  it  to  be 
particles  of  luminous  matter  emitted,  or  thrown  off  by  luminous 
bodies.  The  other  supposes  the  existence  of  a  substance 
called  ether,  which  pervades  all  nature,  and  is  put  into  a 
vibrating  or  wave-like  motion  by  all  luminous  bodies. 

Rays  of  light  proceed  in  straight  lines  from  luminous  bodies, 
unless  interrupted  by  some  intervening  medium.  Light  moves 
with  the  astonishing  velocity  of  200,000  miles  in  a  second  of 
time.  When  a  ray  of  light  falls  on  a  plane  surface,  it  is 
disposed  of  in  one  of  three  ways :  when  the  plane  is  black,  the 
ray  is  all  absorbed:  when  it  is  polished,  the  ray  is  partly 
absorbed  and  partly  reflected :  when  the  plane  is  transparent, 
as  glass  or  water,  it  may  be  partly  absorbed,  partly  transmitted 
and  partly  reflected.  The  law  of  reflection  of  light  is  the  same 
as  that  of  sound:  when  a  ray  of  light  falls  obliquely  on  a 
reflecting  surface,  it  is  reflected  in  the  same  angle  as  the  one 
in  which  it  approached  the  surface ;  thus  the  angles  of  reflec- 
tion and  incidence  are  equal. 

"When  a  ray  of  light  passes  from  a  rarer  to  a  denser  medium, 
it  is  refracted,  or  turned  out  of  its  course :  when  it  passes  from 
a  rare  to  a  denser  medium,  as  from  the  air  into  water,  it  is 


CHEM-J6TRY. 


33 


bent  towards  the  perpendicular:  when  it  passes  from  a  dense 
to  a  rarer  medium,  it  is  turned  from  the  perpendicular. 

Light  is  a  compound  of  seven  colors,  viz :  violet,  indigo,  blue, 
green,  yellow,  orange  and  red.  The  colors  can  be  separated 
by  a  triangular  piece  of  glass,  called  a  prism :  they  possess 
different  degrees  of  refrangibility,  as  will  be  seen  by  the 


Fig.  1.    Solar  Spectrum. 


figure. 


Violet 

Indigo 

Blue 

Green 

Yellow 

Orange 

Red 


[This  cut  shows  the  solar  spectrum  in  the  order  of  its  seven  colors : 
the  violet  appears  most,  and  the  red  least  refracted.] 

There  are  also  heating  rays,  which  attend  the  luminous 
ones:  the  calorific,  or  heating  powers  of  the  red  rays,  are  the 
greatest :  these  powers  diminish  in  the  order  of  the  spectrum, 
from  the  red  to  the  violet,  which  possesses  the  least  of  all. 
Light  is  a  powerful  decomposing  agent :  many  chemical  com- 
pounds, as  the  salts  of  silver,  are  decomposed  by  the  agency 
of  light  alone.  The  influence  of  light  on  vegetation  is  very 
important,  and  will  be  noticed  hereafter.  The  process  of 
taking  phtographic  and  Daguerreotype  pictures,  depends  upon 
the  action  of  light  on  a  sensitive  metallic  surface. 

There  are  several  sources  of  light :  the  great  source  of  light 
which  produces  the  day  to  our  earth,  is  the  sun, — the  moon's 
light  is  only  a  reflected  light  which  it  receives  from  the  sun. 
The  combustion  of  bodies  is  another  source  of  light :  another 
form  of  light  is  called  phosphoresence,  which  is  emitted  by 
certain  bodies,  as  phosphorus,  decayed  wood,  putrid  flesh, 


34  SCIENTIFIC   AGRICULTURE. 

certain  gases,  &c. :  this  is  a  feeble  light,  and  is  only  visible  in 
darkness. 


CALORIC. 


Caloric  is  the  substance  or  agent  which  is  thrown  off  by 
heated  or  burning  bodies,  and  which  produces  the  sensation 
of  heat :  in  common  language  it  is  the  word  used  to  express 
both  the  cause  and  the  effect.  This  agent  possesses  no  appre- 
ciable weight.  Although  it  must  be  substance^  or  material 
in  its  nature, — still  a  body  when  highly  heated  or  charged 
with  caloric,  is  not  sensibly  heavier  raan  when  cold. 

Caloric  appears  to  exist  in  all  bodies.  Heat  and  cold  are 
only  relative  terms ;  when  a  body  is  so  cold  as  to  produce  the 
sensation  of  coldness  to  our  touch,  we  call  it  cold;  on  the 
contrary,  when  it  produces  the  sensation  of  warmth,  we  call  it 
warm, — although  the  absolute  temperature  may  be  the  same 
in  both  cases.  Caloric  always  tends  to  seek  an  equilibrium: 
that  is,  it  constantly  passes  from  the  hotter  to  the  colder 
bodies:  if  a  piece  of  ice  at  32°  be  carried  into  an  atmosphere 
where  the  temperature  is  60°  below  32°,  it  will,  in  changing 
its  temperature  to  that  of  the  surrounding  air,  give  off  60°  of 
heat :  this  illustration  is  sufficient  to  prove  that  the  ice  really 
contains  heat. 

The  expansive  power  of  heat  is  another  property  which 
involves  many  important  facts :  when  caloric  enters  a  body,  it 
is  supposed  that  a  mutual  repulsion  of  its  particles  takes  place, 
so  as  to  partially  overcome  their  cohesive  power,  and  render 
the  body  less  dense.  All  bodies  expand  by  heat, — the  degree 
of  this  expansion,  however,  differs  widely  in  different  bodies. 
The  expansibility  of  fluids  is  greater  than  that  of  solids,  with 
equal  degrees  of  heat. 

All  gases  expand  nearly  equally  with  the  same  degrees  of 
heat :  this  is  not  the  case,  however,  with  the  solids  and  liquids. 
Some  bodies  are  much  better  conductors  of  caloric  than  others : 


CHEMISTRT. 


35 


dense  bodies  are  generally  the  best  conductors  of  caloric: 
the  metals  are  better  conductors  than  wood  or  glass ;  porous 
bodies  conduct  with  less  facility  than  dense  ones.  Snow  is 
porous,  and  therefore  a  poor  conductor  of  caloric, — this  is  why 
the  ground  freezes  less  when  covered  with  snow,  than  when  it 
is  naked. 

The 'different  conducting  power  of  bodies  is  illustrated  by  a 
familiar  example:  on  a  cold  winter  morning  we  find  the 
hearthstone  intensely  cold  to  the  feet,  while  the  woolen  carpet 
is  warm :  now  as  as  they  are  both  exposed  to  the  same  tem- 
perature, the  different  sensation  produced  must  depend  on  the 
different  conducting  power  of  the  two  bodies,  the  one  con- 
ducting off  the  heat  of  the  body  so  rapidly  as  to  produce 
the  feeling  of  coldness,  and  the  other  conducting  but  very 
slightly. 

By  specific  caloric  is  understood,  that  quantity  which  is 
peculiar  to  each  body :  when  one  body  is  found  to  possess  a 
greater  amount  of  caloric  than  another  of  equal  weight,  it  is 
said  to  possess  a  greater  capacity  for  caloric.  The  reason 
why  different  substances  possess  different  capacities  for  caloric, 
is  not  precisely  known.  Bodies  least  dense  appear  generally 
to  possess  the  greatest  capacity  for  caloric, — while  those  more 
dense  possess  the  least.  Hydrogen  gas,  the  lightest  of  all 
known  bodies,  is  said  to  possess  this  capacity  in  the  greatest 
degree. 

When  a  piece  of  cold  iron  is  hammered  for  a  few  minutes, 
it  becomes  hot:  when  sulphuric  acid  is  mixed  with  a  liquid 
less  heavy  and  dense,  as  water  or  alcohol,  the  mixture  becomes 
hot;  when  ice  melts  and  becomes  water,  it  absorbs  heat,  or 
becomes  colder,  as  is  shown  by  a  thermometer.  The  heat 
which  is  developed  in  the  last  case,  and  which  was  before 
inappreciable  to  the  senses,  is  called  latent  heat. 

All  heated  bodies  are  constantly  emitting  or  throwing  off 
caloric;  this  is  called  radiant  caloric, — because  it  is  radiated 


36  SCIENTIFIC    AGRICULTURE. 

in  all  directions  like  the  rays  of  light.  This  effect  is  not 
produced  by  the  gradual  conduction  of  caloric  by  the  ain 
because  the  same  effect  takes  place  in  a  vacuum,  and  in  a 
direction  opposite  to  the  wind.  When  rays  of  heat  fall  upon 
any  body,  they  are,  like  the  rays  of  light,  either  absorbed, 
reflected,  or  transmitted.  Highly  .polished  substances  reflect 
the  heat, — while  rough  surfaces  absorb  it  The  angles  of 
incidence  and  reflection  are  equal  in  radiant  caloric,  as  well  as 
in  light  and  sound.  The  color  of  bodies  has  an  important 
influence  on  their  radiating  power:  dark  colors  radiate  better 
than  light  ones. 

The  transmission  of  heat  through  the  air  takes  place 
without  any  obstruction,  as  is  the  case  with  light;  but  with 
respect  to  other  transparent  media  it  is  different  "  If  a  para- 
bolic or  concave  mirror  be  taken,  and  its  axis  directed  towards 
the  sun,  the  rays  of  both  heat  and  light  will  be  reflected  to 
the  focus,  which  will  exhibit  a  temperature  sufficiently  high  to 
fuse  a  piece  of  metal,  or  fire  a  combustible  body.  If  a  plate 
of  glass  be  now  placed  between  the  mirror  and  the  sun,  the 
effect  will  be  but  little  diminished.  Now  let  the  same  experi- 
ment be  made  with  the  heat  and  light  of  a  common  fire ;  both 
will  be  concentrated  by  reflection  as  before, — but  on  inter- 
posing the  glass  the  heating  effect  of  the  focus  will  be  reduced 
to  almost  nothing,  while  the  light  will  not"  have  undergone 
perceptible  diminution. 

"  Thus  the  rays  of  heat  coming  from  the  sun  traverse  glass 
with  great  facility,  which  is  not  the  case  with  those  emanating 
from  an  ordinary  red  hot  body."  Rays  of  heat  are  not 
transmitted  equally  through  different  bodies  of  equal  trans- 
parency: for  example,  of  100  rays  falling  on  a  crystal  of  rock 
salt,  8  were  intercepted:  of  the  same  number,  glass  inter- 
cepted 61,  and  alum  91.  Color  also  varies  the  power  of 
bodies  to  transmit  heating  rays.  Black  and  opake  bodies  stop 
the  rays  completely.  Rays  of  heat  from  different  sources 


CHEMISTRY.  37 

differ  in  their  properties:  those  proceeding  from  red  hot 
copper  and  fluor  spar,  differ  from  those  from  an  oil  lamp  or 
the  sun.  Cold  is  merely  a  negative  condition  depending  on 
the  absence  of  heat. 

There  are  several  sources  of  caloric,  of  which  the  sun  is  the 
principal,  and  compared  with  which  all  others  are  insignificant. 
The  sun  radiates  heating  as  well  as  luminous  rays,  which 
reach  the  earth,  and  are  partly  absorbed  and  partly  reflected. 
The  combustion  of  bodies  is  another  source, — electricity,  gal- 
vanism, friction,  condensation,  animal  vital  action,  and  chemical 
action,  are  all  sources  of  caloric.  The  earth  is  supposed  to 
contain  in  its  interior  a  vast  amount  of  heat.  The  relations 
of  heat  to  the  growth  of  vegetation  are  important,  and  will  be 
noticed  in  another  place. 

ELECTRICITY. 

Electricity  is  a  fluid  or  principle  pervading  all  nature,  so  far 
as  we  kno\v.  The  first  full  investigation  of  this  extensive  and 
interesting  branch  of  science  was  made  by  Dr.  Franklin ;  and 
although  it  is  only  a  few  years  since,  yet  it  has  become  iden- 
tified with  almost  every  branch  of  physical  science,  and  has 
already  had  an  immense  influence  on  the  moral  and  social, 
as  well  as  commercial  condition  of  the  civilized  world.  We 
still  know  little  of  the  nature  of  electricity ;  although  many  of 
its  properties  and  effects  are  somewhat  well  understood,  still 
all  investigation  and  discovery  has  only  tended  to  render  its 
true  nature  and  phenomena  more  mysterious,  and  its  origin 
more  questionable.  We  see  its  effects,  but  what  it  is,  or 
whence  it  originates,  we  know  not 

But  for  the  sake  of  convenience,  philosophers  have  applied 
certain  terms  to  its  peculiar  properties :  these  terms  in  some 
cases  indicate  particular  effects  and  conditions,  and  in  others 
they  may  be  said  to  be  little  more  than  names  for  our 
ignorance.  Electricity  is  supposed  to  be  a  fluid  which  exists 

4 


38  SCIENTIFIC    AGRICULTURE, 

in  two  opposite  states,  viz :  positive  and  negative.  The  terms 
vitreous  and  resinous  have  also  been  used  to  designate  these 
t\vo  states. 

The  simplest  manner  of  exciting  or  producing  electricity  is 
by  rubbing  a  piece  of  amber  or  sealing  wax  on  dry  cloth* 
when  it  will  be  found  capable  of  attracting  light  bodies,  such 
as  feathers,  bits  of  thread,  paper,  &c.  The  body  so  affected  is 
called  an  electric,  and  is  said  to  be  in  a  state  of,  .electrical 
excitation.  The  sealing  wax  or  amb^r  in  this  case  is  in  the 
positive  state,  or  is  positively  electrified,  while  the  feather  or 
other  substance  attracted  to  it  is  in  the  negative  state,  or  is 
negatively  electrified.  It  is  impossible  to  develop  one  of  these 
states  or  phenomena  without  at  the  same  time  developing  the 
other  also.  After  adhering  to  the  electrical  body  for  a  few 
seconds  it  will  fall  off,  it  being  charged  with  electricity  and  in 
the  positive  state  like  the  electric :  if  the  electric  be  excited 
again,  and  the  feather  presented  to  it,  it  will  be  strongly 
repelled  and  tend  to  fly  off — this  is  called  electrical  repulsion. 

The  passage  of  the  electric  spark  is  instantaneous:  it  appears 
also  to  be  confined  to  the  surface  of  bodies  in  its  passage. 
Bodies  which  allow  electricity  to  pass  over  them  are  called 
conductors:  these  are  non-electrics, — that  is,  they  cannot  be 
excited  by  friction  so  as  to  produce  electricity:  on  the  con- 
trary, those  bodies  which  can  be  electrically  excited  will  not 
conduct  the  fluid;  so  that  non-conductors  are  electrics,  and 
non-electrics  are  conductors. 

The  electric  spark  fires  gaseous  mixtures,  and  is  capable  of 
producing  intense  heat:  electricity  also  decomposes  solutions 
of  metallic  oxides  and  salts.  Some  fishes,  as  the  torpedo  and 
electrical  eel,  possess  an  electrical  apparatus  within  their 
bodies,  which  is  capable  of  producing  severe  shocks  upon 
other  animals ;  and  this  is  done,  too,  at  the  will  of  the  fish.  It 
has  been  satisfactorily  settled  by  Prof.  Matteitcci,  that  electri- 
city has  nothing  to  do  with  the  action  of  the  nervous  system 


CHEMISTRY.  39 

of  animals,  and  that  life  and  all  the  vital  functions  are  not 
dependent  upon  it  for  their  existence  and  action.  Electricity 
gives  polarity  to  iron,  and  is  supposed  to  be  the  cause  of,  or 
identical  with  magnetism. 

The  polarity  of  the  earth  is  supposed  to  depend  upon  the 
passage  of  electrical  currents  around  it.  Electricity  is  desig- 
nated according  to  its  different  states,  by  the  terms  statical 
and  dynamical.  Statical  electricity  treats  of  the  properties  of 
the  fluid  at  rest  or  in  a  state  of  equilibrium.  Dynamical 
electricity  treats  of  the  fluid  in  motion,  or  as  it  displays  its 
phenomena  while  under  experiment.  The  upper  regions  of 
the  atmosphere  are  generally  in  a  positive  state;  in  cloudy 
weather,  the  distribution  of  the  fluid  is  disturbed,  and  this 
gives  rise  to  the  phenomena  of  thunder  and  lightning.  Gal- 
vanism, as  well  as  magnetism,  is  supposed  to  be  identical 
with,  or  a  modification  of,  electricity. 

Electricity  is  developed  in  various  ways,  by  different  kinds 
of  apparatus  which  cannot  be  described  in  this  place.  All  the 
forms  of  electricity  are  applied  to  useful  purposes,  to  con- 
siderable extent,  in  the  arts  and  sciences.  It  remains  an 
unsettled  problem  as  yet,  whether  electricity  in  any  form  can 
be  made  available  to  the  growth  of.  vegetation :  its  efficacy, 
also,  in  the  healing  art,  is  not  as  much  relied  upon  as  in 
former  years ;  this,  like  all  newly  discovered  remedial  agents, 
has  had  its  day  of  glory,  and  has,  probably,  by  means  of 
correct  observation  and  careful  experiment,  fallen  to  about  its 
proper  standard. 

NOTE. — The  term  PVROGEX  has  been  proposed  instead  of 
Electricity :  the  term  signifies  generator  of  heat  or  fire. 


CHAPTER  III. 


GENERAL   PROPERTIES    OF    GASES. 

GA&  is  an  elastic  fluid  or  air,  formerly,  but  not  now,  supposed 
to  be  produced  by  the  union  of  some  body  with  caloric:  most 
gases  are  inappreciable  by  the  senses,  except  that  of  feeling, — 
having  neither  taste,  color  nor  odor.  Some  have  a  specific 
gravity  greater,  and  others  less  than  common  or  atmospheric 
air.  Several  gases  have  been  liquified  by  the  conjoined  action 
of  cold  and  pressure :  several  have  also  been  solidified  by  the 
conjoined  action  of  intense  cold  and  the  pressure  of  from  two 
to  fifty  atmospheres.  The  product  of  this  experiment  is  in 
most  cases  an  exceedingly  transparent  crystaline  substance. 
Gases,  like,  liquids,  have  but  a  slight  power  of  conducting 
caloric:  their  conducting  power  is  so  slight  as  to  be  imper- 
ceptible, and  they  are  therefore  called  non-conductors  of 
caloric. 

AH  gases  possess  a  certain  amount  of  specific  caloric, — the 
precise  quantity  which  they  respectively  contain  has  not  been 
determined.  Gases  exist  throughout  nature,  and  may  be 
produced  by  artificial  means.  Some  of  them  are  capable  of 
being  respired,  without  injury  to  health,  while  others  cannot, 
without  producing  deleterious  or  fatal  effects.  Some  are,  in 
common  language,  supporters  of  combustion,  while  others  are 
not.  Those  gases  only  which  are  necessary  to  be  known  in 
their  relations  to  agriculture,  will  bo  described  in  this  work, 


CHEMISTRY.  41 

OXYGEN ITS    PROPERTIES    AND    RELATIONS. 

•  Oxygen  is  an  invisible,  transparent  fluid,  without  taste  or 
odor ;  respirable  and  necessary  to  organic  life,  with  a  specific 
gravity  of  1.2G,  air  being  1.  It  has  the  most  extensive 
affinity  of  all  known  substances.  It  combines  with  metals, 
forming  oxides  and  acids :  it  combines  also  with  other  gases, 
and  is  an  important  element  in  water  and  the  atmosphere:  it 
js  usually  called  a  supporter  of  combustion, — it  exists  in  great 
abundance  in  nature,  and  may  be  obtained  by  chemical  process 
from  several  substances, — most  easily,  perhaps,  from  black 
oxide  of  manganese.  It  is  said  that  nearly  one-third  of  the 
weight  of  all  the  solid  matter  of  the  globe  consists  of  this 
gas.  The  combustion  of  all  fires  depends  on  the  presence  of 
oxygen, — a  lighted  taper  burns  with  greatly  increased  bril- 
liancy in  pure  oxygen  gas. 

No  plant  can  vegetate  without  it,  although  no  plant  will 
long  survive  after  being  placed  in  this  gas  alone.  No  animal 
can  respire  for  a  single  minute  without  oxygen,  but  when 
immersed  in  a  jar  of  it,  the  vital  processes  are  all  increased 
until  fever  succeeds,  and  the  animal  dies.  "According  to 
Dr.  Henry,  100  volumes  of  water  absord  only  3j  of  oxygen.'' 
The  combining  number  of  oxygen  is  8. 

HYDROGEN ITS    PROPERTIES    AND    RELATIONS. 

Hydrogen  gas  is  the  lightest  of  all  known  substances,  being 
fourteen  times  lighter  than  common  air, — destitute  of  taste, 
color  or  odor :  it  is  combustible,  but  not  a  supporter  of  com- 
bustion; it  is  incapable  of  sustaining  animal  life,  though  it 
is  destitute  of  poisonous  properties,  —  an  animal  dies  when 
immersed  in  it  from  want  of  oxygen, — the  death  results  from 
its  negative  condition,  rather  than  from  any  positive  injury 
which  is  sustained  by  breathing  the  gas.  It  exists  in  nature 
in  less  abundance  than  carbon  or  oxygen,  and  is  not  known  to 
occur  in  a  free  or  uncombined  state.  It  forms  a  small  part  of 
all  animal  and  vegetable  substances,  and  constitutes  one-ninth 

*4 


42  SCIENTIFIC  AGRICULTURE. 

part  of  the  weight  of  water :  it  does  not  occur  in  combination 
witli  any  of  the  mineral  masses  of  the  globe,  except  coal, — and 
this  is  itself  of  vegetable  origin.  This  gas  burns  with  a  pale 
yellow  flame, — its  combustion  is  attended  by  the  formation  of 
water. 

Plants  do  not  grow  in  this  gas,  but  gradually  wither  and 
die.  Its  specific  gravity  is  0.0687:  100  gallons  of  water 
absorb  1-i-  gallons  of  this  gas.  It  is  the  gas  used'  for  inflating 
balloons.  Hydrogen  is  readily  obtained  by  the  action  of  sul- 
phuric acid  on  zinc  or  iron.  It  is  necessary  to  the  growth  of 
vegetation,  but  not  in  a  free  or  uncombined  state.  The  com- 
bining number  of  hydrogen  is  1. 

CARBON ITS    PROPERTIES    AND    RELATIONS. 

Carbon  exists  in  a  pure  and  crystaline  form  in  the  diamond ; 
graphite,  or  black  lead,  and  common  charcoal,  are  examples  of 
carbon  of  impure  varieties.  It  constitutes  a  large  proportion 
of  all  animal  and  vegetable  substances:  nearly  all  plants  in  a 
dried  state,  contain  from  40  to  50  per  cent,  by  weight,  of 
carbon.  This  substance  is  of  great  importance  in  the  art  of 
culture,  on  account  of  its  power  of  absorbing  large  quantities 
of  the  gases  and  vapors  of  the  atmosphere, — this  is  especially 
true  of  charcoal,  or  carbon  in  a  light  and  porous  form.  Char- 
coal is  used  for  filtering  impure  water,  which  it  cleanses  f  om 
decayed  animal  or  vegetable  substances,  and  coloring  matters 
which  are  held  in  solution:  it  is  used  also  in  clarifying  syrups 
and  oils:  it  has  the  power  of  absorbing  noxious  vapors  and 
gases,  which  result  from  the  decomposition  of  animal  and 
vegetable  matters,  and  of  preventing  or  retarding  the  decay 
of  all  organic  substances. 

The  gases  and  moisture  which  are  arrested  and  retained  by 
carbon  in  the  soil,  are  again  readily  yielded  up  to  the  roots  of 
plants,  during  the  process  of  growth.  Several  important  ends 
are  subserved  by  carbon  in  the  soil :  it  purifies  impure  air  and 


CHEMISTRY.  43 

water,  which  would  not  nourish  plants,  but  on  the  contrary 
prove  destructive  to  their  tender  germs  and  roots :  it  absorbs 
gases  from  the  air  as  before  stated ;  prevents  putrefaction  (and 
acidity  to  some  extent,)  in  the  soil,  and  is  itself  an  indispen- 
sable element  in  vegetation. 

Carbonic  acid  is  a  gas  or  air,  which  results  from  the  com- 
bustion of  charcoal, — when  charcoal  is  burned,  it  nearly  all 
disappears  in  the  form  of  gas,  leaving  only  a  small  residue  of 
ash  behind.  Carbonic-acid-gas  is  heavier  than  common  air, 
colorless,  invisible,  having  an  agreeable  pungent  taste  and 
odor,  but  cannot  be  respired  without  poisonous  effects  resulting 
from  it.  Carbonic  acid  may  be  obtained  for  experiment  from 
white  marble,  which  is  a  carbonate  of  lime,  or  from  common 
limestone.  The  combining  number  of  carbon  is  6. 

It  is  neither  combustible  nor  a  supporter  of  combustion, — a 
lighted  taper  dipt  into  a  jar  this  gas  is  instantly  extinguished ; 
— it  often  exists  in  deep  wells,  mines,  caverns  and  pits,  and 
proves  fatal  to  those  who  enter  them, — the  precaution  should 
therefore  always  be  taken  to  let  down  a  lighted  candle,  which 
will  determine  the  presence  or  absence  of  the  gas.  It  is  this 
gas  also  which  proves  so  deleterious  in  ill  ventilated  rooms 
heated  by  coal  fires.  It  is  formed  during  the  combustion  of 
all  wood,  coal  and  oil  fires, — it  is  generated  by  the  respiration 
of  animals  and  the  growth  and  decay  of  vegetation:  it  is 
produced  also,  together  with  alcohol,  during  the  fermentation 
of  sugar.  It  is  evolved  in  vast  quantities  from  the  ground  in 
volcanic  countries,  and  exists  in  combination  with  metallic 
oxides  in  the  earth :  these  compounds  are  called  carbonates, 
the  most  important  of  which  is  carbonate  of  lime.  This  gas 
has  an  acid  reaction :  water  dissolves  its  own  volume  of  it,  and 
forms  an  agreeable  sparkling  solution:  it  is  this  gas  which 
escapes  during  the  effervesence  of  soda  water  and  various 
kinds  of  beer. 

It  is  apparent  that  the  excessive  accumulation  of  so  poi- 


... 


SCIENTIFIC    AGRICULTURE. 


ra  gas  must  prove  destructive  to  all  animal  and  vegeta- 
e,  if  some  means  were  not  provided  by  which  it  could  be 
removed  as  fast  as  it  is  generated  by  natural  causes :  growing- 
vegetables,  although  they  could  not  live  in  this  gas  alone, 
require  a  constant  supply  of  it  as  an  element  of  food, — and 
this  is  just  sufficient  to  preserve  a  wonderful  balance  in  this 
respect  throughout  all  nature. 

According  to  Liebig,  a  healthy  man  expires  from  his  lungs 
5  ounces  a  day,  or  100  pounds  a  year,  of  carbon:  a  horse,  or 
cow,  expires  six  times  this  amount, — or  600  pounds  a  year. 
ISTow  if  the  crops  of  an  acre  of  land  require  2  tons  of  carbon  in 
a  year,  (which  is  Johnston's  estimate,)  a  farm  of  25  acres 
would  require,  if  all  cultivated,  50  tons  of  carbon.  If  the 
family  of  the  farm  be  reckoned  at  5  adults,  and  the  stock  at  2 
horses,  5  cattle,  40  sheep,  5  hogs,  including  the  poultry,  the 
amount  of  carbon  they  would  all  expire  would  be  not  far  from 
10  tons  in  a  year.  They  would  then  supply  from  this  source 
alone  one-fifth  of  all  the  carbon  requisite  to  grow  the  crops  of 
the  farm. 

Coal  which  is  dug  from  the  earth  and  burned  as  fuel,  adds 
to  the  carbon  of  the  atmosphere  a  new  portion,  which  had 
been  buried  in  the  earth,  and  consequently  lost  to  vegetation 
for  many  centuries.  The  coal  consumed  annually  in  Great 
Britain,  contains  14  millions  of  tons  of  carbon,  which  would 
supply  this  element  to  the  crops  of  twenty-eight  millions  of 
acres. — [Johnston.]  Decay  of  vegetation,  when  extensive,  as 
in  the  peat  bogs  of  Europe,  the  jungles  of  India,  and  the 
tropical  forests  of  Africa  and  South  America,  furnishes  im- 
measurable quantities  of  carbon. 

The  final  result  of  this  eremacausis,  (slow  combustion,)  or 
slow  decay,  is  the  same  as  that  of  ordinary  combustion:  the 
immediate  result,  however,  is  different:  decay  furnishes  much 
less  carbon  in  proportion  to  the  matter  consumed  than  com- 
bustion; decay  produces,  also,  light  carburetted  hydrogen, 


CHEMISTRY.  45 

which  combustion  does  not.     The  latter  gas  is  changed  by  the 
electricity  of  the  air  to  carbonic  acid  and  water. 

The  evolution  of  carbon  from  volcanoes,  and  fissures  in  the 
earth  in  volcanic  regions,  is  immense.  In  the  ancient  volcanic 
region  Eifel,  on  the  bank  of  the  Rhine,  an  annual  evolution 
takes  place,  according  to  Bischoff,  of  27,000  tons  of  carbon. 
Some  carbon  is  absorbed  by  the  waters  of  seas  and  oceans, 
which  is  not,  as  far  as  we  know,  restored  to  the  atmosphere. 
Vegetable  matters  carried  away  by  water,  deposited  and  em- 
bedded in  beds  of  sand  and  clay,  are  thus  prevented  from 
decaying,  and  their  carbon  is  consequently  lost.  These  are 
two  sources  of  loss  of  carbon:  and  although  the  balance 
between  its  production  and  consumption  is  nearly  equal,  "still, 
according  to  Prof.  Johnston,  there  is  supposed  to  be  a  slight, 
permanent  loss  to  the  entire  mass  of  our  atmosphere. 

NITROGEN ITS    PROPERTIES    AND    RELATIONS. 

Nitrogen  is  widely  diffused  through  nature,  constituting 
nearly  four-fifths  of  the  atmosphere,  and  existing  in  many 
vegetable,  and  most  animal  substances.  It  is  destitute  of 
color,  taste  or  odor,  and  is  a  little  lighter  than  common  atr ;  it 
is  incapable  of  supporting  combustion  or  animal  life, — but,  like 
hydrogen,  it  has  no  positively  poisonous  properties.  Water 
absorbs  it  in  very  small  quantity:  it  is  in  fact  distinguished  for 
negative  properties, — the  reason  why  it  does  not  sustain  com- 
bustion and  animal  life,  appears  to  be  merely  the  Absence  of 
oxygen.  Its  use  in  the  atmosphere  seems  to  be  only  to  dilute 
the  oxygen  sufficiently  to  render  it  fit  for  respiration. 

Nitrogen  combines  with  oxygen  and  forms  acids  and  oxides. 
Its  combining  number  is  14.  Nitrogen  may  be  obtained  by 
burning  phosphorus  under  a  bell  glass  over  water.  It  does 
not  enter  into  the  composition  of  any  of  the  mineral  con- 
stituents of  the  earth's  crust,  except  coal,  which  is  of  vegetable 
origin.  Nitrogen  forms  an  important  part  in  the  growth  of 
both  animals  and  plants. 


46  SCIENTIFIC    AGRICULTURE, 

GASEOUS  COMPOUNDS. 


WATER ITS   PROPERTIES  AXD  RELATIONS. 

Pure  water  is  transparent,  colorless,  tasteless,  and  inodor- 
ous: it  is  a  compound  of  the  gases  oxygen  and  hydrogen,  in 
the  proportion  of  8  parts  of  the  former  to  1  of  the  latter,  by 
weight, — or  by  volume,  1  of  oxygen  to  2  of  hydrogen.  It 
boils,  under  ordinary  circumstances,  at  212°  and  freezes  at 
82o,  Fall.  :  its  greatest  density  is  at  about  40°, — at  212°,  it 
takes  the  form  of  vapor  or  steam,  and  is  thus  increased  to 
1700  times  its  former  bulk,  and  is  about  two-fifths  lighter  than 
common  air, — it  consequently  rises  and  becomes  diffused 
through  the  air. 

Water  evaporates  at  all  temperatures  above  freezing:  it  is 
780  times  heavier  than  common  air, — a  cubic  foot  weighs  six- 
ty-two and  a  half  pounds.  It  is  the  standard  of  specific  gravity 
for  all  bodies, — its  number  in  this  respect  is  unity  or  1. 

The  purest  water,  except  that  which  has  been  distilled,  falls 
from  the  clouds  in  the  form  of  rain  and  snow  at  the  close  of  a 
shower:  all  other  natural  waters  contain  various  soluble  and 
insoluble  gaseous,  mineral  and  organic  matters, — among  which 
are,  carbonic  acid,  carbonate  of  lime,  ammonia,  salts  of  iron, 
soda,  iodine,  bromine,  magnesia,  silica,  sulphur  and  others. 
"Water  possesses  the  most  extensive  solvent  power  of  all  known 
liquids :  it  absorbs  gases  from  the  air  to  a  considerable  amount : 
these  are  again  expelled  by  boiling,  and  are  altered  in  their 
proportions  from  those  which  constitute  the  atmosphere. 

Water  mixes  with,  or  dissolves  all  liquids  except  those  of  an 
oily  nature :  it  dissolves  also  most  salts,  many  gums,  coloring 
matters,  and  slowly  dissolves  many  rocks  and  earths:  water 
has  a  wide  range  of  affinities  for  animal,  vegetable  and  mine- 
ral elements,  which  it  exercises  without  being  itself  decom- 
posed, It  is  the  most  universally  diffused  through  the  three 


CHEMISTRY  47 

kingdoms  of  nature,  of  any  substance:  it  enters  largely  into 
the  composition  of  living  animal  bodies,  and  constitutes,  ac- 
cording to  Johnston,  half  the  weight  of  all  green  or  newly 
gathered  vegetables  which  are  cultivated  for  the  use  of  man. 

Without  water,  neither  animals  nor  plants  could  exist,  (with 
their  present  organization,)  the  earth  would  become  a  scorched 
and  sterile  waste :  many  compounds  resulting  from  chemical 
affinities  which  require  the  presence  of  water,  would  be  un- 
known :  the  varieties  of  climate  which  now  exist  would  also 
to  a  great  extent  be  unknown.  Water  in  its  relations  to  vege- 
table life,  and  also  its  meteorological  influences,  will  be  more 
particularly  discussed  in  a  subsequent  part  of  this  book. 

THE    ATMOSPHERE ITS  PROPERTIES  AXD  RELATIONS. 

The  atmosphere  which  we  breathe  is  an  immense  ocean  of 
gaseous  fluid  :  the  depth  of  this  ocean  is  about  45  miles,  at 
the  bottom  of  which  we  live, — or  rather,  it  extends  about  45 
miles  above  the  surface  of  the  earth,  which  it  entirely  sur- 
rounds. It  is  composed  of  the  two  gases  oxygen  and  nitro- 
gen, in  volume  in  the  proportions  of  about  21  of  the  former 
to  T9  of  the  latter  in  100.  It  contains  also,  according  to 
Sausseur,  ^  jV ^  °f  ^s  bulk  of  carbonic  acid. 

The  quantity  of  this  gas  is  greater  in  cities  than  in  the  coun- 
try, slightly  less  in  the  air  over  the  seas  and  great  lakes, — it 
is  less  over  a  wet  than  a  diy  soil,  and  by  day  than  by  night. 
The  air  is  imbued  with  watery  vapor  which  varies  in  different 
climates :  it  holds  in  suspension,  traces  of  various  animal  and 
vegetable  matters  and  ammonia.  Heat  and  electricity  also 
exist  more  or  less  at  all  times  in  the  atmosphere.  Air  diffuses 
itself  everywhere,  penetrates  the  minutest  recesses  of  every 
porous  body,  and  presses  with  the  almost  incredible  weight  of 
15  pounds  to  every  square  inch  of  the  earth's  surface:  it  is 
transparent,  colorless,  invisible,  elastic,  tasteless  and  inodorous. 
The  two  essential  elements  of  the  atmosphere,  viz.  oxygen  and 


48  SCIENTIFIC  AGRICULTURE. 

nitrogen,  arc  not,  according  to  Dr.  Kane  and  others,  in  a  state 
of  chemical  union,  but  only  a  mixture. 

The  specific  gravity  of  air  is  about  7 SO  times  less  than  that 
of  water;  100  cubic  inches  weigh  about  31  grains.  A  column 
of  air  45  miles  high  just  balances  a  column  of  water  of  the 
same  diameter,  33  feet  high,  or  a  column  of  mercury  29 
inches  high :  hence  water  cannot  be  raised  in  a  pump  on  the 
principle  of  atmospheric  pressure,  more  than  about  33  feet, — 
hence  also  the  mercury  in  the  barometer  tube  is  about  29 
inches  high.  The  air  expands  and  becomes  less  dense  by 
heat ;  hence  warm  air  always  rises,  and  cold  air  descends :  the 
composition  of  the  air  is  everywhere  nearly  uniform, — its  com- 
plete and  beautiful  adaptation  to  the  wants  of  animal  and 
vegetable  life  will  be  more  apparent  the  more  we  become 
acquainted  with  its  nature  and  laws :  without  it  no  animal  or 
plant  could  exist  for  a  single  day.  Its  relations  to  vegetation 
more  especially,  will  be  described  hereafter. 

CARBONIC    OXIDE. 

Carbonic  oxide  is  a  colorless,  inodorous  gas,  composed  of 
one  equivalent  of  carbon,  united  to  one  of  oxygen :  it  extin- 
guishes a  lighted  taper,  takes  fire  at  the  same  time  itself,  and 
burns  with  a  pale  blue  flame,  forming  carbonic  acid.  It  is 
lighter  than  common  air,  nearly  insoluble  in  water,  and  does 
not  support  animal  life.  It  is  produced,  together  with  car- 
bonic acid,  by  the  combustion  of  coal  fires.  "  It  is  not  known 
to  occur  in  nature,  or  to  minister  directly  to  the  growth  of 
plants." 

OXALIC    ACID. 

This  is  another  compound  of  carbon  and  oxygen,  in  the 
proportions  of  two  of  the  former  to  three  of  the  latter.  It  is 
found  in  the  interior  of  many  plants,  as  the  sorrel,  rhubarb, 
bistort,  gentian,  chick  pea,  and  several  lichens :  it  is  not  known 
to  contribute  to  their  growth,  but  appears  to  be  the  result  of  a 


CHEMISTRY  49 

gaseous  combustion  consequent  upon  their  growth.  It  is 
found  combined  with  potash  and  lime  in  the  form  of  salts 
called  oxalate  of  potash  and  lime :  it  is  one  of  the  most  impor- 
tant of  the  organic  bodies. 

Crystalized  oxalic  acid  is,  in  transparent  bodies,  intensely- 
sour,  and  very  poisonous.  This  acid  is  not  found  in  the  soil, 
nor  in  the  waters  which  reach  the  roots  of  plants :  the  simple 
process  by  which  it  is  elaborated  in  the  interior  of  plants  will 
be  described  hereafter.  Oxalic  acid  neutralizes  alkalies  per- 
fectly, and  forms  several  important  salts.  There  exists  a  rela- 
tion between  carbonic  acid,  carbonic  oxide  and  oxalic  acid, 
which  will  be  described  under  the  head  of  vegetable  physi- 
ology, 

LIGHT    CARBURETTED    HYDROGEN. 

This  is  a  light,  inflammable  gas,  which  is  formed  by  the 
decomposition  of  organic  substances  at  high  temperature :  in 
warm  weather  it  may  be  seen  rising  in  bubbles  from  marshy 
places  and  stagnant  pools,  when  vegetables  are  in  process  of 
decomposition.  This  gas  is  colorless,  destitute  of  taste  or  odor, 
about  half  the  weight  of  common  air:  a  lighted  taper  is 
extinguished  by  it,  while  the  gas  ignites  and  burns  with  a  pale 
yellow  flame :  animals  immersed  in  this  gas  cease  to  breathe 
almost  instantly.  This  is  the  gas  which  exists  in  marshes 
under  the  name  of  marsh  (fas, — and  also  in  coal  mines  under 
the  name  of  fire  damp:  violent  explosions  sometimes  took 
place  in  coal  mines  by  the  ignition  of  this  gas  mixed  with 
oxygen,  from  the  miners'  lamps,  previous  to  the  invention  of 
the  safety  lamp  by  Dr.  Davy.  It  consists  of  one  equivalent 
of  carbon  and  two  of  hydrogen. 

This  gas,  together  with  carbonic  acid,  is  given  off  during 
the  fermentation  of  compost,  and  all  large  collections  of  vege- 
table matter.  "  It  is  supposed,  [says  Johnston,]  by  many,  to 
minister  to  the  nourishment  of  plants:  it  is,  however,  very 

o 


50  SCIENTIFIC    AGRICULTURE. 

sparingly  soluble  in  water,  so  that  in  a  state  of  solution,  it 
cannot  enter  largely  into  the  pores  of  the  roots,  even  though  it 
be  abundantly  present  in  the  soil:"  it  probably  exists  in  all 
well  manured  soils;  "but  the  extent  to  which  it  really  acts  as 
food  to  living  vegetables  is  entirely  unknown." 

NITRIC    ACID ITS    PROPERTIES    AND    RELATIONS. 

Nitric  acid  is  a  compound  of  one  part  nitrogen  and  five  of 
oxygen:  liquid  nitric  acid,  when  pure,  is  colorless,  intensely 
sour  and  corrosive,  heavier  than  water,  and  boils  at  187°  Fah- 
renheit. If  exposed  to  the  air,  it  gives  off  white  fumes  with 
the  disengagement  of  part  of  its  oxygen,  becomes  yellow,  and 
is  converted  into  nitrous  acid. 

"  True  nitric  acid  [says  Dr.  Kane]  has  never  been  isolated ; 
that  substance  generally  spoken  of  as  nitric  acid,  is  a  compound 
of  it  with  water ;  it  is  a  nitrate  of  water,  or,  as  it  is  popularly 
termed,  liquid  nitric  acid,  or  aquafortis."  This  acid  decom- 
poses all  organic  substances  rapidly,  neutralizes  the  alkalies, 
and  oxidizes  the  metals,  for  which  it  has  a  strong  affinity. 

This  acid  is  not  found  in  nature  in  an  uncombined  state;  but 
it  occurs  in  combination  with  soda,  lime  and  potash,  in  the 
form  of  nitrates,  in  many  tropical  countries.  In  the  West 
Indies,  vast  quantities  of  nitrate  of  potash  (salt  petre)  are 
formed  by  nature :  in  Chili  and  Peru,  immense  beds  of  nitrate 
of  soda  are  also  found.  The  origin  of  these  salts  is  as  follows : 
rain  water,  particularly  that  which  falls  during  a  thunder 
shower,  contains  nitrate  of  ammonia,  when  the  water  comes  in 
contact  with  the  potash,  soda  and  lime  of  the  soil, — having  a 
stronger  affinity  for  them  than  for  the  ammonia,  it  unites  with 
them  and  forms  the  salts,  while  the  ammonia  is  again  set  free 
and  escapes  into  the  air.  These  salts  are  soluble  in  water,  and 
are  important  agents  in  promoting  the  growth  of  cultivated 
plants. 


CHEMISTRY.  51 

AMMONIA ITS    PROPERTIES    AND    RELATIONS. 

Ammonia  is  a  colorless  gas,  having  a  strong,  pungent  odor 
and  alkaline  taste:  it  is  composed  of  one  proportion  of  nitro- 
gen and  three  of  hydrogen:  its  equivalent  number  then  is  17. 
It  is  slightly  combustible,  but  does  not  support  combustion. 
"  Ammunia  is  rapidly  absorbed  by  water,  which  takes  up  780 
times  its  volume  at  32°:"  this  is  called  water  of  ammonia,  or 
spirits  of  hartshorn, — it  has  a  specific  gravity  about  one-tenth 
less  than  water,  and  boils  at  120°.  In  its  power  of  neutrali- 
zing acids,  it  ranks  next  to  lime,  being  a  powerful  base:  it 
forms,  with  the  metallic  salts  and  with  acids,  many  compounds. 
Ammoniacal  gas  does  not  support  respiration, — animals  are 
speedily  suffocated  by  it,  and  living  plants  confined  in  it  soon 
wither  and  die.  It  is  absorbed  largely  by  porous  bodies,  such 
as  charcoal,  burnt  brick,  burnt  clay,  &c., — charcoal  is  said  to 
absorb  95  times  its  own  bulk. 

Ammonia  is  sufficiently  caustic  to  destroy  both  animal  and 
vegetable  substances.  It  is  remarkable  that  the  two  gases 
which  form  ammonia,  having  neither  taste  nor  odor  when 
separate,  produce,  when  united  in  certain  proportions,  a  gas  so 
intensely  strong,  pungent,  and  acrid.  Ammonia  being  only 
about  three-fifths  the  weight  of  common  air,  it  rises  and 
mingles  with  the  air  when  it  is  set  free,  unless  it  is  retained 
by  some  substance  with  which  it  will  unite  and  form  a  solid 
substance  not  volatile.  The  salts  of  ammonia  are  easily  soluble 
in  water. 

Ammonia  exists  in  considerable  abundance  in  nature, — it  is 
almost  universally  diffused,  but  does  not  enter  as  a  constituent 
into  any  of  the  mineral  masses  of  the  earth's  crust.  It  is  found 
mostly  in  a  state  of  combination  with  acids,  in  the  form  of 
nitrate,  muriate  and  carbonate  of  ammonia.  It  is  evolved 
largely  by  the  decay  of  animal  and  vegetable  matters,  and 
does  not  remain  long  in  a  free  state  in  the  air,  but  combines 


52  SCIENTIFIC    AGRICULTURE. 

with  acid  vapors  which  it  meets  in  the  atmosphere,  and  forms 
other  compounds. 

The  salts  of  ammonia  are  decomposed  by  lime,  magnesia, 
potash  and  soda,  and  the  ammonia  is  set  free  in  the  gaseous 
state :  the  ease  with  which  compounds  of  ammonia  are  decom- 
posed, constitutes  one  of  its  most  valuable  properties,  and 
renders  it  peculiarly  adapted  to  the  various  offices  it  performs 
in  the  processes  of  vegetation.  In  the  air,  the, soil,  or  the 
interior  of  plants,  it  is  easily  decomposed  by  electricity  and  the 
alkaline  bases  before  named. 

"  The  hydrogen  it  contains  in  so  large  quantity,  [says  Prof. 
Johnston,]  is  ready  to  separate  itself  from  the  nitrogen  in  the 
interior  of  the  plant,  and,  in  concert  with  the  other  organic 
elements  introduced  by  the  roots  or  the  leaves,  to  aid  in  pro- 
ducing the  different  solid  bodies  of  which  the  several  parts  of 
plants  are  made  up.  The  nitrogen  also  becomes  fixed  in  the 
colored  petals  of  the  flowers,  in  the  seeds,  and  in  other  parts, 
of  which  it  appears  to  constitute  a  necessary  ingredient,  passes 
off  in  the  form  of  new  compounds,  in  the  insensible  perspira- 
tion or  odoriferous  exhalations  of  the  plant, — or  returning  with 
the  downward  circulation,  is  thrown  off  by  the  root  into  the 
soil  from  which  it  was  originally  derived."  The  transforma- 
tions which  actually  take  place  in  the  interior  of  plants,  is  not 
yet  perfectly  understood,  although  many  of  them  can  be 
clearly  explained.  The  agency  of  ammonia  and  its  various 
compounds,  in  the  promotion  of  vegetation,  is  both  powerful 
and  important, — and  will  be  explained  more  fully  in  a  subse- 
quent chapter,  as  will  also  its  formation  and  sources. 


CHAPTER  IV. 


ELEMENTARY    BODIES. 

ELEMENTARY  or  simple  bodies,  are  those  which  consist  of  a 
single  substance,  and  cannot  be  decomposed,  or  reduced  to  a 
more  simple  form.  They  are  such  as  have  hitherto  resisted 
all  attempts  at  decomposing  them;  but  still,  new  methods  of 
analysis  may  yet  enable  the  chemist  to  prove  them  to  be  of  a 
compound  nature, — and  indeed  this  has  already  been  the  case 
with  some  which  were  formerly  considered  elementary.  These 
simple  bodies  are  about  sixty  in  number,  so  far  as  yet  known ; 
but  chemical  analysis  will  doubtless  make  us  acquainted  with 
others.  Several  attempts  at  classification  of  these  bodies  have 
been  made ;  but  none,  as  yet,  has  been  on  all  accounts  unob- 
jectionable. 

One  division  is,  into  metallic  and  non-metallic  substances: 
this  division,  although  entirely  arbitrary  and  less  philosophical 
than  some  others,  is  still  the  most  convenient,  and  sufficiently 
explicit  for  our  present  purpose.  It  is  the  one  adopted  by 
Doct.  Fownes. 

Non-Metallic  Elements. 

Oxygen,  Chlorine,  Silicon, 

Hydrogen,  Iodine,  Boron, 

Nitrogen,  Bromine,  Sulphur, 

Carbon,        '  Fluorine,  Selenium. 

*5 


04  SCIENTIFIC  AGRICULTURE. 

Elements  of  Intermediate  Characters. 
Phosphorus,  Arsenic,  Tellurium. 

Metals. 

Antimony,  Uranium, 

Chromium,  Cerium, 

Vanadium,  Lantanum, 

Tungsten,  Platinum, 

Rhodium,  Palladium, 

Iridium,  Yttrium, 

Osmium,  Bismuth, 

Gold,  Tin, 

Alumnium,  Mercury, 

Glucinum,  Silver, 

Zirconium,  Lead, 

Thorium,  Barium, 

Cadmium,  Strontium, 

Copper,  Calcium, 

Iron,  Magnesium, 

Manganese,  Zinc, 

Lithium,  Nickel, 

Sodium,  Cobalt, 

Pelopium,  Potassium, 

Niobium.  Ruthenium, 

Molybdenum,  Erbium, 

Columbium,  Terbium. 

Titanium, 

These  sixty  simple  elements  combine  with  each  other  in 
such  manner  as  to  form  the  innumerable  compounds  which 
make  up  the  whole  animal,  vegetable  and  mineral  kingdoms. 
So  far  as  we  know,  all  ponderable  bodies  in  the  universe  are 
only  the  varied  compounds  of  these  few  substances.  The 
imponderable  agents,  light,  caloric,  electricity,  galvanism,  and 
magnetism,  and  the  vital  principle,  are  not  well  understood  in 
their  natures  and  composition ;  so  that  nothing  can  be  predi- 


CHEMISTRY.  5o 

catcd  as  to  their  relation  in  composition  to  the  simple  bodies. 
Such,  only,  of  these  bodies  will  be  described,  as  are  necessary 
to  be  known  in  their  relations  to  Agricultural  Science. 

ACIDS. 

Acids  are  chemical  compounds  whioh  are  capable  of  uniting 
in  different  proportions  with  alkalies,  to  form  a  third  class 
called  salts :  by  this  union  the  properties  of  both  the  acids  and 
alkalies  are  destroyed,  or  neutralized.  Most  acids  have  a  sour 
taste,  —  there  are,  however,  some  exceptions:  they  change 
vegetable  blues  to  red ;  they  are  electro-negative,  and  there- 
fore have  a  strong  affinity  for  the  electro-positive  compounds, 
such  as  alkalies,  alkaline  earths  and  oxides.  Nearly  all  of 
them  contain  oxygen;  when  the  oxygen  is  not  present,  it  is 
replaced  by  hydrogen:  they  are  therefore  called  by  some 
writers,  oxacids  and  hydracids. 

Acids  are  divided  again  into  mineral  and  vegetable;  the 
mineral  are,  nitric,  sulphuric,  muriatic,  &c. :  the  vegetable  acids 
are  very  numerous, — acetic,  citric  and  tartaric  are  examples. 
Most  vegetable  acids  contain  both  oxygen  and  hydrogen.  The 
mineral  acids  are  heavier  than  water,  exceedingly  caustic  and 
corrosive, — destroying  both  animal  and  vegetable  textures. 
Some  acids  are  in  a  fluid,  and  others  in  a  dry,  solid  or  crys- 
taline  form.  They  unite  with  water  in  all  proportions.  They 
absorb  water  from  the  atmosphere,  if  exposed,  and  become 
weaker  in  strength,  diminished  in  weight,  and  increased  in 
bulk. 

ALKALIES. 

Alkalies  are  a  class  of  bodies  possessing  properties  opposite 
to  those  of  acids,  having  a  strong  affinity  for,  and  uniting  with 
them  in  different  proportions,  to  form  salts,  as  before  stated. 
They  are  incombustible,  caustic  and  acrid,  very  soluble  in 
water,  and  change  vegetable  blues  and  red  to  green,  and  yellow 
to  brown, — in  fact  they  destroy  or  change  the  vegetable  colors 


50  SCIENTIFIC    AGRICULTURE. 

generally.  They  are  divided  into  fixed  and  volatile, — the 
fixed  alkalies  are  potash  and  soda:  these  do  not  evaporate,  like 
ammonia,  which  is  therefore  called  a  volatile  alkali.  They 
have  a  sharp,  pungent  taste,  destitute  of  acidity,  and,  with  the 
exception  of  ammonia,  have  but  little  odor.  They  unite  with 
the  oils  and  fats,  and  form  the  well  known  compound,  soap. 
There  is  also  a  class  of  compounds  called  alkaline  earths,  as 
lime,  barytes,  magnesia  and  strontium.  The  alkalies  and  alka- 
line earths  are  electro-positive  in  their  affinities. 

SALTS. 

Salts  constitute  a  numerous  class  of  compounds,  which 
result  from  the  chemical  union  of  acids  and  alkalies.  They 
are  of  three  kinds,  viz :  acid,  basic  and  neutral. 

Acid  salts  contain  an  excess  of  acid ;  most  of  them  are  not 
really  acid  salts,  but  double  salts,  of  which  one  base  is  water ; 
bi-carbonate  of  potash  is  an  example. — [Kane.]  The  sub- 
stance which  unites  with  an  acid  to  form  a  salt,  is  called  a 
lase, 

Basic  salts  are  those  in  whicli  there  is  more  than  one 
equivalent  of  base  for  one  of  acid,  as  in  sulphate  and  nitrate 
of  copper. 

Neutral  salts  do  not  manifest  either  acid  or  alkaline  proper- 
ties on  vegetable  colors, — they  have  neither  an  acid  nor  an 
alkaline  taste,  and  generally  consist  of  one  equivalent  of  acid 
and  one  of  base. 

Double  salts  are  formed  by  the  union  of  two  simple  salts; 
in  general  both  salts  contain  the  same  acid,  but  different  bases. 
Salts  usually  crystalize  in  regular  determinate  forms;  some 
being  in  prisms  or  crystals,  having  three,  four,  five,  six, 
&c.,  sides,  and  as  many  angles.  Most  salts  contain  some 
water  in  a  loose  state  of  combination :  this  is  called  their  water 
of  crystalization.  This  water  evaporates  from  some  salts,  and 
they  become  a  dry  powder, — such  are  called  effervescent  salts: 


CHEMISTRY.  57 

others  absorb  more  water  from  the  atmosphere,  and  are  dis- 
solved in  it, — these  are  called  deliquescent  salts. 

Salts  may  effervesce  or  deliquesce  without  destroying  their 
peculiar  qualities  or  the  chemical  union  between  the  acid  and 
base.  Salts  dissolved  by  water  again  crystalize  when  the 
water  is  evaporated.  The  crystals  of  some  salts  are  very 
small,  as  in  epsom  salts, — in  others  they  are  large,  as  in  chro- 
mate  of  potash. 

ORGANIC    ELEMENTS    OF    PLANTS. 

Organic  bodies  possess  a  much  greater  complexity  of  com- 
position, than  substances  of  mineral  origin.  The  organic 
bodies  are  distinguished  from  the  inorganic  by  the  nature  of 
their  elements :  the  products  of  the  vegetable  kingdom  surpass 
in  number  and  variety  those  of  the  mineral, — but  still  those  of 
the  former  consist  almost  exclusively  of  six  elements,  viz :  car- 
bon, oxygen,  hydrogen,  nitrogen,  sulphur,  and  pkospkortt?:  of 
these  six,  carbon  alone  exists  in  all  bodies  of  both  animal  and 
vegetable  origin.  Sulphur  and  phosphorus  are  met  with  but 
seldom :  iodine  and  bromine  exist  in  marine  plants  and 
sponges;  besides  these,  plants  contain  in  most  cases,  iron, 
silicon,  calcium,  potassium,  magnesium,  manganese,  and  some- 
times fluorine.  These  are  called  the  ultimate  elements  of 
plants, — because  they  are  the  final  result  of  analysis,  and 
cannot  themselves  be  reduced  to  a  more  simple  form,  or  sepa- 
rated into  other  elements. 

These  combine  in  such  a  manner  as  to  form  the  various 
substances,  such  as  starch,  gum,  sugar,  and  an  almost  endless 
variety  of  others  found  in  plants.  These  latter  are  called 
organic  products,  or  immediate  or  proximate  elements,  because 
they  are  more  easily  separated  and  obtained  without  a  rigid 
analysis.  As  a  general  rule,  bodies  most  complex  in  their 
number  of  elements  and  simplicity  of  equivalent  relations,  are 
the  weakest,  and  least  capable  of  resisting  those  disturbing 


58  SCIENTIFIC  AGRICULTURE. 

forces  which  tend  to  produce  decomposition,  or  transformation 
of  their  elements.  Substances  of  different  properties,  but 
identical  in  composition,  are  called  isomeric  bodies. 

These  bodies,  although  containing  the  same  ultimate  ele- 
ments, may  be  as  widely  different  in  their  chemical  relations 
as  bodies  which  have  no  elements  in  common.  Oil  of  turpen- 
tine and  oil  of  citron  are  isomeric  compounds, — each  being 
composed  of  carbon  5 — hydrogen  4. 

LIGNINE. 

The  proper  wood  of  plants,  when  separated  by  chemical 
means  from  all  soluble  substances,  is  called  lignine.  It  is 
composed  of  carbon,  hydrogen  and  oxygen, — these  are  its 
constant  elements,  whether  it  be  obtained  from  the  porous 
willow,  dense  boxwood,  or  the  fibres  of  linen  and  cotton.  The 
hydrogen  and  oxygen  exist  in  the  same  proportions  as  in 
water;  so  that  lignine  is  apparently  only  carbon  and  water: 
but  distillation  does  not  prove  this  to  be  the  case. 

Pure  lignine  is  white:  it  undergoes  no  decomposition  in  dry 
air,  or  under  water  which  contains  no  air;  but  by  the  joint 
action  of  heat  and  air  it  undergoes  changes  which  produce 
another  series  of  compounds,  very  different  from  itself.  Woody 
fibre  is  arranged  in  cells  and  tubes :  the  walls  of  these  cells 
and  tubes  are  composed  of  cellular  woody  fibre,  and  covered 
by  a  solid  substance  called  incrusting  matter.  It  is  difficult  to 
separate  the  two,  so  as  to  determine  by  analysis  the  precise 
difference  in  their  composition.  It  is  evident  that  woody  fibre 
constitutes  the  great  mass  of  all  forest  trees,  and  also  of  the 
dried  stalks  and  roots  of  most  plants. 

STARCH. 

Starch  is  probably  the  most  abundant  product  of  vegeta- 
tion, with  the  exception  of  woody  fibre.  It  is  obtained  from 
the  flower  of  all  the  grains,  many  roots,  the  .pith  and  seeds  of 
many  other  plants.  Starch  is  obtained  in  the  form  of  a  fine 


CHEMISTRY.  oU 

powder,  consisting  of  rounded,  shining  white  particles.  They 
are  tasteless  and  inodorous,  and  when  kept  dry  undergo  no 
change  in  any  length  of  time.  Starch  is  insoluble  in  cold 
water  or  alcohol,  but  dissolves  readily  in  hot  water,  and  forms 
a  jelly.  Starch,  like  lignine,  is  composed  of  carbon,  hydrogen 
and  oxygen.  Starch  is  a  delicate  test  for  the  presence  of 
iodine. 

Arroiv root,  sago,  tapioca,  inulme  and  lichenine  are  varieties 
of  starch.  It  is  frequently  deposited  among  the  woody  fibres 
and  in  the  inner  bark  of  trees,  as  the  willow,  beech  and  pine. 
This  is  the  reason,  [says  Prof.  Johnston,]  that  the  branch  of  a 
willow  takes  root  so  readily,  and  also,  that  the  bark  of  trees  is 
used  in  some  countries  as  food. 

GUM. 

Gum  arabic  is  a  familiar  example  of  this  class  of  substances ; 
the  gum  from  peach  and  plumb  trees  is  similar  in  constitution. 
Pure  gum  is  light  colored,  having  a  sweetish  taste,  destitute  of 
odor,  insoluble  in  alcohol,  soluble  in  water,  with  which  it  forms 
an  adhesive  mucilage.  Gum  is  composed  of  carbon,  hydrogen 
and  oxygen :  it  exists  in  the  seeds  and  other  parts  of  many 
plants.  Arabine,  carasine,  bassorine,  dextrine,  and  traga- 
canthine  are  all  varieties  of  gum:  this,  as  well  as  starch,  is 
highly  nutricious  as  food. 

SUGAR. 

Sugar  exists  in  many  plants, — but  is  obtained  principally 
from  sugar  cane,  sugar  maple,  and  beet  root.  Pure  sugar  is 
in  large  transparent  crystals,  having  a  pure  sweet  taste,  desti- 
tute of  odor,  soluble  in  water,  highly  nutricious.  Its  constit- 
uent elements  are  carbon,  hydrogen  and  oxygen.  Grape 
sugar,  sugar  of  milk,  and  sugar  of  mushrooms,  are  all  va- 
rieties. 


60  SCIENTIFIC    AGRICULTURE. 

MUTUAL  RELATIONS  OF  LIGNINE,  STARCH,  GUM  AND  SUGAR. 

It  is  a  remarkable  fact,  that  these  four  substances,  though 
possessing  properties  so  entirely  different,  are  composed  of  the 
same  elements  in  the  same  proportions.  This  fact,  so  evident 
to  the  analytical  chemist,  is  still  little  more  comprehensible  to 
him,  after  his  most  profound  investigations,  than  to  the  most 
unlearned.  And,  although  we  can  readily  separate  the  ele- 
ments of  these  bodies,  we  cannot  combine  the  same  elements 
so  as  to  form  any  one  of  them.  The  formulae  below  show 
their  constitution. 

Woody  fibre  is  composed  of     C.  12,  H.  10,  0.  10. 

Starch  "          "          «      C.  12,  H.  10,  0.  10. 

Gum  "          •'          "     C.  12,  H.  10,  0.  10. 

Cane  sugar     «          "          «      C.  12,  H.  10,  0.  10. 
These  four  substances  are  capable  of  being  transformed  ono 
into  another,  as  woody  fibre  into  starch,  starch  into  sugar,  gum 
into  sugar,  &c.,  as  will  be  hereafter  described. 

GLUTEN. 

Gluten  exists  in  the  flour  of  wheat,  rye,  barley  and  oats, 
from  which  it  may  be  obtained  by  washing  the  paste  or  dough 
for  a  long  time  in  water.  It  is  a  soft,  tenacious,  elastic,  grayish 
substance,  with  very  little  taste  or  odor.  It  is  nearly  insoluble 
in  water,  but  easily  dissolved  by  alcohol,  acids  and  alkalies : 
when  moist  gluten  is  dried  at  212°;  it  becomes  a  semi-trans- 
parent, yellowish,  brittle  mass,  resembling  glue.  Wheat  con- 
tains more  gluten  than  any  of  the  other  grains:  it  contains, 
according  to  its  quality,  from  8  to  35  per  cent.  Gluten  is 
highly  nutricious:  it  is  composed  of  carbon,  hydrogen,  oxygen 
and  nitrogen. 

ALBUMEN. 

Albumen  is  a  gelantinous,  colorless  substance,  without  taste 
or  smell,  dissolved  by  acids  and  alkalies,  but  insoluble  in 


CHEMISTRY.  61 

alcohol  and  water.  Albumen  resembles  the  white  of  eggs, 
which  is  animal  albumen;  it  abounds  in  the  juices  of  many 
plants,  as  cabbage,  turnips,  <fec. :  its  composition  is  identical 
with  that  of  gluten,  which  is  as  follows: 

Carbon,  54.76 
Hydrogen,  7.06 
Oxygen,  20.06 
Nitrogen,  18.12 

100 

When  exposed  to  air  and  moisture  it  undergoes  decomposi- 
tion, which  is  attended  by  the  formation  of  vinegar  and  ammo- 
nia. It  possesses  highly  nutrient  properties. 

WAX. 

Wax  is  found  in  many  plants :  beeswax  may  be  taken  as 
the  type  of  this  class  of  bodies.  It  is  insoluble  in  water  or 
cold  alcohol,  but  dissolved  by  boiling  alcohol,  which  separates 
it  into  two  proximate  principles,  viz:  cerine  and  myridne. 
Beeswax  melts  at  144°,  and  when  freed  from  its  yellow 
coloring  matter,  has  a  white  crystaline  appearance,  Cerine, 
boiled  with  a  solution  of  potash,  forms  soap.  Wax  is  supposed 
to  be  derived  from  the  oils  of  plants. 

RESIN. 

Resin  is  obtained  from  the  pitch  of  various  of  the  coniferous 
family,  such  as  the  pine,  hemlock,  fir,  &c.  Resin  is  highly 
inflammable,  insoluble  in  water,  but  readily  dissolved  by 
alcohol  and  essential  oils:  the  principal  resins  are,  common 
rosin,  copal,  mastic  and  elemi.  Common  rosin  is  what  remains 
after  the  distillation  of  pitch  to  obtain  spirits  of  turpentine. 

CAMPHOR. 

Camphor  is  a  gum-like,  white,  brittle,  semi-transparent  sub- 
stance, having  a  strong  peculiar  odor  and  an  acrid  bitter  taste. 

6 


62  SCIENTIFIC    AGRICULTURE. 

It  exists  in  several  plants,  but  is  found  in  most  abundance  in 
the  camphor  tree.  It  is  highly  inflammable,  and  resembles  in 
some  respects  the  resins :  it  is  nearly  insoluble  in  water,  but 
dissolved  by  alcohol  and  oils. 

CAOUTCHOUC. 

Caoutchouc,  or  India  Rubber,  is  the  product  of  several 
trees  in  tropical  countries,  from  which  it  exudes  in  tlie  form  of 
a  milky  juice  which  hardens  by  contact  with  the  air.  It  is 
insoluble  in  water  or  alcohol,  and  dissolves  but  imperfectly  in 
ether;  its  proper  solvent  is  volatile  oils:  oil  of  turpentine  dis- 
solves it,  but  it  dries  imperfectly  afterwards.  At  a  tempera- 
ture a  little  above  that  of  boiling  water  it  melts  and  never 
resumes  its  elasticity :  in  its  properties,  it  possesses  considera- 
ble resemblance  to  the  resins:  it  may  be^converted  into  a 
volatile  oil  by  distillation. 

FIXED  OILS. 

Oils  are  divided  into  two  classes,  viz:  fixed  and  volatile: 
the  former  are  capable  of  being  distilled  without  decomposi- 
tion,— the  latter  are  not.  The  animal  and  vegetable  oils  agree 
in  their  properties  very  nearly  in  every  respect.  The  fixed 
oils  are  obtained  by  pressure,  from  the  seeds  of  various  plants, 
as  the  castor  bean,  flax  seed,  <fcc. 

They  have  little  taste  or  odor,  are  lighter  than  water,  con- 
geal at  a  lower  temperature,  and  require  a  higher  heat  than 
that  of  boih'ng  water  to  evaporate  them.  They  are  highly 
nutricious,  and  combine  with  soda  to  form  soap:  by  contact 
with  air  they  become  rancid  and  gummy :  they  are  all  inso- 
luble in  water,  and,  with  the  exception  of  castor  oil,  but 
slightly  so  in  alcohol:  they  dissolve  easily  in  ether  and  the 
volatile  oils. 

VOLATILE  OILS. 

Volatile  or  essential  oils  are  numerous  in  the  vegetable 
kingdom,  and  give  to  plants  their  peculiar  odors:    they  are 


CHEMISTRY.  63 

obtained  by  distillation.  Most  of  them  are  lighter  than  water, 
highly  combustible,  and  dissolve  in  alcohol  to  form  essences: 
when  pure,  they  are  colorless,  and  evaporate  from  paper 
without  leaving  a  greasy  stain,  as  fixed  oils  do:  they  do  not 
form  soap  with  alkalies, 

VEGETABLE    ACIDS. 

Acids  are  numerous  in  the  vegetable  kingdom,  and  possess 
much  interest  and  importance ;  but  the  limits  of  this  book  will 
not  admit  of  a  detailed  account  of  them :  they  constitute  but  a 
small  part  of  the  plants  from  which  they  are  derived.  The 
most  important  are  the  acetic,  oxalic,  tartaric,  citric  and  malic 
acids.  The  general  properties  of  acids  have  already  been 
described. 

VEGETABLE    ALKALIES. 

Alkalies  exist  in  all  plants,  and  always  in  the  form  of  salts, 
or  in  combination  with  an  acid.  Potash,  lime  and  soda, 
although  found  in  plants  in  greater  abundance  than  the 
others,  are  not  vegetable  alkalies :  the  true  vegetable  alkalies 
are,  morphia,  quinia,  strychnia,  <fec. 

METALLIC  OXIDES  AND  EARTHS  found  in  plants  have  already 
been  named,  and  their  properties  will  be  described  in  another 
chapter.  The  few  organic  proximate  elements  of  plants  which 
have  been  briefly  described,  are  but  a  comparatively  small 
part  of  the  whole  number:  only  such  as  possess  most  interest, 
and  are  most  common  and  necessary  to  be  understood,  have 
been  selected. 

DIASTASE. 

Diastase  is  a  white,  tasteless  powder,  formed  during  the 
process  of  malting  barley,  and  also  during  the  germination  of 
plants.  The  properties  of  diastase  are  not  well  understood, — 
it  is  supposed  to  be  the  first  product  of  the  putrefactive  fer- 
mentation of  vegetable  gluten  and  albumen. 


64  SCIENTIFIC    AGRICULTURE. 

EXTRACTIVE    MATTER. 

Extractive  matter  (apotheme)  exists  in  vegetables,  and  may 
be  obtained  by  steeping  them  in  hot  water,  and  then  evapo- 
rating the  water,  when  a  brown  powder  will  remain,  which  is 
but  slightly  soluble  in  water  or  alcohol,  but  soluble  in  alkalies. 
Its  nature  is  not  well  understood ;  Dr.  Kane,  however,  supposes 
it  may  be  identical  with  ulmic  or  hamic  acid.  It  is  not  nutri- 
cious. 

TANNIN. 

Tannin  exists  in  the  bark  of  most  trees,  but  most  abun- 
dantly in  the  bark  of  the  oak,  horse  chestnut  and  hemlock.  It 
is  an  astringent  brownish  powder,  soluble  in  alcohol  and  water. 
It  has  an  astringent  taste  and  is  destitute  of  odor :  it  combines 
with  animal  gelatine  and  forms  an  insoluble  precipitate ;  hence 
by  soaking  the  skins  of  animals  in  a  solution  containing  tannin, 
it  is  converted  into  leather,  which  is  no  longer  subject  to 
putrefaction.  It  is  composed  of  carbon,  hydrogen  and  oxygen : 
it  is  not  nutricious :  it  precipitates  most  metallic  solutions,  and 
is  hence  used  in  practical  chemistry  as  a  re-agent. 

COLORING   MATTER. 

The  matter  which  constitutes  the  basis  of  vegetable  colors 
is  found  in  most  plants.  "The  organic  coloring  principles, 
[says  Dr.  Fownes,]  with  the  exception  of  one  red  dye,  cochi- 
neal, are  all  of  vegetable  origin."  The  art  of  coloring  is  based 
upon  the  affinity  which  exists  between  the  coloring  matter  and 
the  fibres  of  the  different  fabrics  to  be  colored.  This  is 
stronger  in  woolen  than  in  cotton  and  linen ;  hence  in  dyeing 
the  two  latter  a  third  substance,  called  a,  mordant,  is  used, 
which  strengthens  their  affinity:  for  this  purpose,  salts  of 
alumina,  iron  and  tin  are  used. 

The  coloring  principle  of  vegetable  blues  is  indigo:  that  of 
madder  red  is  alizarine:  of  madder  yellow,  xanthine:  the 
green  color  of  plants  depends  upon  a  substance  called  chloro- 


CHEMISTRY.  65 

phylle.  The  coloring  principle  of  logwood  is  hcematoxyline : 
carmine  is  a  beautiful  pink  color  derived  from  the  cochineal 
insect:  several  substances  produce  yellow  and  brown. 

Nearly  all  vegetable  colors  are  destroyed  by  the  action  of 
solar  light, — and  all  of  them,  without  exception,  by  the  action 
of  chlorine  gas :  acids  and  alkalies  destroy  or  change  them. 
No  coloring  principle  has  yet  been  found  in  plants,  capable  of 
being  transferred  to  other  bodies  so  as  to  produce  a  green: 
greens  are  therefore  produced  by  the  action  of  blues  upon  a 
base  of  yellow.  Substantive  colors  are  those  which  combine 
directly  with  the  fibres  of  cloth  without  the  intervention  of  a 
mordant :  adjective  colors  require  the  assistance  of  a  mordant 
to  make  them  permanent, 

INORGANIC  ELEMENTS  OF  PLANTS. 

Besides  the  organic  elements  which  enter  into  the  compo- 
sition of  plants,  and  which,  as  before  stated,  are  themselves  in 
most  cases  composed  of  the  four  principal  elements,  carbon, 
oxygen,  hydrogen  and  nitrogen, — there  are  several  inorganic 
substances,  which  are  constantly  present  in  all  plants,  and  in 
about  the  same  relative  proportions  in  the  same  plant  in  all 
cases.  These  are  in  combination  with  the  gases  and  with  one 
another.  Chlorine,  iodine,  sulphur,  phosphorus,  potassium, 
sodium,  calcium,  magnesium,  aluminum,  silicon,  iron  and  man- 
ganese, 

CHLORINE. 

Chlorine  is  a  yellowish  green  gas,  having  a  pungent,  suffo- 
cating odor ;  it  is  soluble  in  water,  extinguishes  a  lighted  taper, 
has  a  specific  gravity  of  2.47,  and  when  submitted  to  the 
pressure  of  four  atmospheres,  is  condensed  into  a  limpid, 
yellow  liquid.  This  gas  is  a  supporter  of  combustion,  but  not 
of  animal  life :  a  piece  of  phosphorus,  gold  leaf,  potassium  or 
sodium,  introduced  into  it,  inflame  and  burn  spontaneously. 
Chlorine  has  but  little  affinity  for  oxygen,  its  chemical  pre- 

e* 


66  SCIENTIFIC   AGRICULTURE. 

ferences  being  principally  hydrogen  and  the  metals :  it  is  not 
found  in  an  uncombined  state  in  nature.  The  most  charac- 
teristic property  of  this  gas  is  its  bleaching  power ;  it  decom- 
poses readily  the  most  permanent  organic  coloring  principles ; 
the  presence  of  water  is  necessary  to  develop  the  bleaching 
properties  of  chlorine.  'This  gas  is  a  highly  disinfecting  agent. 
Common  salt  is  a  compound  of  chlorine  and  sodium. 

IODINE. 

Iodine  is  a  solid  substance,  in  shining  lead-colored  scales. 
It  is  volatilized  or  converted  into  vapor  by  a  moderate  haat, — 
the  vapor  has  a  beautiful  violet  color,  and  an  odor  resembling 
chlorine.  It  is  soluble  in  water,  and  more  perfectly  so  in 
alcohol.  It  is  obtained  from  the  ashes  of  marine  plants,  but 
has  not  as  yet  been  detected  in  any  of  the  plants  cultivated 
for  food.  Both  plants  and  animals  confined  in  the  vapor  of 
iodine  soon  perish. 

SULPHUR. 

Sulphur  exists  in  considerable  abundance  in  nature;  the 
most  common  source  of  the  sulphur  of  commerce  is  volcanic 
action :  it  is  sublimed  and  thrown  out  in  large  quantities  from 
the  earth, — it  exists  also  in  natural  waters.  It  is  a  yellowish 
green  powder,  having  little  taste  or  smell, — it  is  but  slightly 
soluble  in  water.  When  heated  it  exhales  white  fumes  of  an 
intensely  suffocating  odor, — these  fumes  are  called  sulphurous 
add.  This  gas  is  destructive  to  both  animal  and  vegetable 
life:  it  possesses  bleaching  properties.  There  are  several 
compounds  of  sulphur  which  are  essential  to  the  growth  of 
vegetation. 

PHOSPHORUS. 

Phosphorus  is  a  solid  substance,  having  the  consistence  of 
wax,  and  of  a  pale  yellow  color:  when  exposed  to  the  air,  it 
takes  fire  spontaneously  and  burns  with  a  pale  blue  flame, 
scarcely  visible  except  in  the  dark.  When  heated,  however, 


CHEMISTRY. 


67 


it  takes  fire  and  burns  with  a  brilliant  flame  and  intense  light, 
with  the  evolution  of  dense  white  fumes. 

It  is  not  found  in  nature  in  an  uncombined  state,  "and  is 
not  known  [says  Johnston,]  to  be  susceptible  of  any  useful 
application  in  practical  agriculture."  Phosphoric  acid  results 
from  the  combination  of 'the  fumes  of  burning  phosphorus 
with  the  oxygen  of  the  atmosphere.  It  has  the  characteristic 
properties  of  acids,  and  unites  with  lime,  soda  and  potash,  to 
form  phosphates.  This  acid  is  not  found  in  nature  in  a  free 
state, — but  the  compounds  of  phosphorus  are  extensively  dif- 
fused throughout  nature,  and  are  essential  to  the  growth  of 
all  cultivated  plants. 

CATALOGUE  OF   THE  COMPOUNDS  DERIVED  FROM   THE    INORGANIC 
ELEMENTS  OF  PLANTS. 


Sulphurous  acid, 

Sulphuric       " 

Phosphoric     " 

Potash, 

Soda, 

Lime, 

Magnesia, 

Chloride  of  Potassium, 
"  Sodium, 

"  Calcium, 

"  Magnesium, 

First  Chloride  of  Iron, 

Second     "        "      " 

Carbonate  of  Soda, 

Bi-carbonate       " 

Nitrate  " 

Sulphate  « 

Phosphate  " 

Bi-phosphate      " 


Alumina, 
Silica, 

Protoxide  of  Iron, 
Peroxide          " 
Protoxide  of  Magnesia, 
Sesquioxide  " 

Peroxide  " 

Sulphuret  of  Potassium, 
Sodium, 
Calcium, 
Iron, 

Bi-sulphuret       " 
Carbonate  of  Potash, 
Bi-carbonate         " 
Sulphate  " 

Nitrate  " 

Binoxalate  " 

Bitartrate  " 

Phosphate  « 


SCIENTIFIC    AGRICULTURE. 

Carbonate  of  Lime,  Bi-p'uospliate  of  Potash, 

Sulphate  "  Carbonate  of  Magnesia, 

Nitrate  "  Bi-carbonate         " 

Phosphate         "  Sulphate 

Bi-phosphate     "  Nitrate  *' 

Silicate  of  Potash,  Phosphate  " 

Bi-silicate         "  Sulphate  of  Alumina, 

Silicate  of  Soda,  Phosphate  " 

Bi-silicate      "  Silicate  " 

Silicate  of  Lime,  Carbonate  of  Iron, 

"  Magnesia,  Sulphate  " 

Carbonate  of  Magnesia, 
Sulphate 

These  are  not  all  the  compounds  found  in  plants;  but  they 
are  those  which  exist  in  most  plants,  and  which  are  more  or 
less  essential,  in  some  quantity,  to  the  healthy  growth  and 
maturity  of  the  various  parts  of  the  vegetable  organization. 


CHAPTER  V. 


FERMENTATION. 


Fermentation  is  a  peculiar  decomposition  or  transformation  of  the  ele- 
ments of  a  complex  organic  substance,  by  the  agency  of  some 
external  disturbing  force  different  from  ordinary  chemical  attraction, 
as  heat,  air,  or  contact  with  some  other  body  similarly  affected. 

Liebig. 


THE  compounds  which  are  capable  of  fermentation,  or  any 
similar  change,  are  those  in  which  a  weak  affinity  or  equilib- 
rium exists,  and  is  consequently  easily  disturbed  and  overcome, 
by  several  different  agencies,  such  as  heat,  acids,  oxygen, 
chlorine,  &c.  If  we  add  to  a  solution  of  sugar  and  water  a 
small  quantity  of  any  organic  substance  which  is  itself  in  the 
act  of  slow  decomposition,  the  sugar  becomes  affected  in  the 
same  way,  and  is  changed  to  carbonic  acid  and  alcohol 

This  is  called  vinous  fermentation:  another  form  of  vinous 
fermentation  is  that  which  takes  place  in  the  transformation  of 
must  into  wine:  when  the  expressed  juice  of  the  grape  is 
exposed  to  a  temperature  of  about  70°  F.,  its  own  temperature 
is  raised,  carbonic  acid  is  given  off,  a  scum  rises  to  the  surface* 
and  a  sediment  subsides  to  the  bottom,  and  the  must  is  changed 
to  wine.  This  is  the  simplest  case  of  fermentation :  yeast  is 
peculiarly  effective  in  producing  this  kind  of  fermation.  Yeast 
is  the  product  of  the  vegetable  gluten  or  albumen  in  fermen- 


0  SCIENTIFIC    AGRICULTURE. 

tation.  Tiie  fermenting  power  of  yeast  is  destroyed  by  boiling, 
by  alcohol,  by  many  salts  and  acids,  and  generally  by  all  those 
agencies  which  render  albimnn  and  gluten  insoluble. 

Besides  yeast,  there  are  several  vegetable  substances,  as 
gluten,  albumen,  caseine  and  fibrine,  which,  when  in  a  state  of 
decomposition,  act  as  ferments  on  a  solution  of  sugar.  The 
same  effect  is  produced,  also,  by  animal  gluten,  albumen,  flesh 
and  blood,  after  putrefaction  has  commenced.  When  wine 
and  cider  are  exposed  to  the  air  at  a  certain  temperature,  a 
second  fermentation,  called  the  acetous,  takes  place,  and  they 
are  changed  to  vinegar:  during  this  change  oxygen  is  absorbed 
from  the  air,  and  carbonic  acid  is  evolved :  "  but  the  apparent 
cause  of  the  formation  of  vinegar  is  the  abstraction  of  hydrogen 
from  the  alcohol,  so  as  to  leave  the  remaining  elements  in  such 
proportions  as  to  constitute  acetic  acid.  The  presence  of  nitro- 
gen seems  to  be  necessary  to  the  composition  of  all  ferments. 
The  precise  nature  of  the  changes  which  take  place  during 
fermentation  are  not  yet  precisely  understood  or  explained. 

"  We  can  offer  no  other  explanation  of  these  facts  of  fermen- 
tation than  this,  that  when  a  body  in  a  state  of  progressive 
change,  the  particles  of  which  are  in  a  state  of  motion,  is 
placed  in  contact  with  another  body,  the  particles  of  which 
are  in  a  state  of  unstable  equilibirum,  the  amount  of  motion 
mechanically  communicated  to  the  particles  of  the  latter  from 
those  of  the  former  is  sufficient  to  overturn  the  existing  equi- 
librium, and  by  the  formation  of  a  new  compound,  establish  a 
new  equiblirum  more  stable  under  the  given  circumstances." 

[Turner. 

METAMORPHOSIS  OF  ORGANIC  ELEMENTS. 

There  are  certain  organic  compounds  which,  from  the  com- 
plexity of  their  constitution  and  consequent  weakness  of  affinity, 
are  peculiarly  disposed  to  decomposition  and  change  of  elemen- 
tary form.  Among  these  are  starch,  gum,  sugar  and  lignine, 
the  first  three  of  which  are  composed  of  the  same  elements  in 
the  same  proportions. 


CHEMISTRY.  71 

These  are  disposed  to  change  of  elementary  form  whenever 
the  balance  of  opposing  forces  is  destroyed:  that  is,  whenever 
by  the  agency  of  some  external  disturbing  force,  as  heat,  air  or 
water,  the  affinity  which  holds  these  elements  together  is  over- 
come, the  elements  are  separated  entirely,  or  one  element  is 
replaced  by  another ;  and  thus  lignine  is  changed  into  starch, 
starch  into  sugar,  &c. 

This  intimate  relation  of  composition  among  these  substances 
renders  it  plain  that  they  may  all  occur  together  in  the  same 
plant,  and  that  when  one  occasionally  disappears  from  the 
plant,  it  may  be  replaced  entirely  or  in  part  by  another;  and 
this  is  really  the  case.  Lignine  or  woody  fibre  may  be  changed 
to  starch  by  boiling  sawdust  in  water  so  as  to  separate  all 
soluble  matters,  then  drying  it  in  an  oven  and  fermenting  with 
yeast.  In  this  way  the  author  has  made  bread  of  beech  wood, 
which  was  but  little  inferior  to  that  made  from  unbolted  wheat 
flour. 

Woody  fibre  may  be  transformed  to  starch,  also,  by  the 
action  of  sulphuric  acid  or  caustic  potash. 

Starch,  when  gradually  heated  to  a  temperature  not  ex- 
ceeding 300°  F.,  acquires  a  brownish  tint,  and  is  changed  to 
gum.  Starch  may  be  changed  to  gum  by  dissolving  it  in  hot 
water,  and  allowing  it  to  remain  in  a  cold  place  for  a  few 
months ;  or  it  may  be  changed  more  rapidly  by  boiling  it  in 
water  for  a  length  of  time.  By  the  action  of  sulphuric  acid, 
also,  starch  may  be  changed  to  gum,  and  this  gum  again  into 
grape  sugar. 

Gum  arable  may  be  changed  to  sugar  by  the  agency  of 
chalk  and  sulphuric  acid. — [Berzelius. 

Cane  sugar  which  is  crystalized,  if  heated  to  a  temperature 
of  360°  F.,  gives  off  two  atoms  of  water  and  is  changed  to 
caramel:  this  is  an  uncrystallizable  sugar,  containing  one  pro- 
portion of  oxygen  and  one  of  hydrogen  less  than  cane  sugar. 
Cane  sugar  may  be  changed  to  grape  sugar  by  digesting  it  in 


V2  SCIENTIFIC    AGRICULTURE. 

dilute  sulphuric  acid  at  a  gentle  heat.     The  formula  for  these 
two  varieties  of  sugar  is  as  follows : 

Cane  Sugar.  Dry  Grape  Sugar. 

Carbon,       12,  Carbon,       12, 

Hydrogen,  10,  Hydrogen,  12, 

Oxygen,      10.  Oxygen,       12. 

From  the  fact  that  we  can  produce  these  metamorphoses  at 
pleasure,  it  is  easy  to  conceive  that  they  may  take  place  even 
more  readily  and  perfectly  in  the  vegetable  organization,  than 
by  the  comparatively  clumsy  operations  of  the  chemical  labor- 
atory. This  is  one  of  an  infinite  number  of  the  beautiful 
processes  of  nature  which  modern  chemistry  has  discovered. 


PART    II, 


GEOLOGY. 


CHAPTER  I. 

GEOLOGY  investigates  the  nature,  composition,  origin,  struc- 
ture, and  arrangement  of  the  materials  of  which  the  earth 
is  composed.  Geology  may  be  divided  into  three  parts,  viz: 
1.  Chemical  Geology,  which  investigates  the  chemical  nature 
and  composition  of  the  various  materials  of  which  the  earth 
is  made  up.  2.  Mechanical  Geology,  which  treats  of  the 
arrangement,  structure  and  relative  position  of  these  various 
materials.  3.  Historical  Geology,  which  treats  of  then:  relative 
ages  and  origin,  and  the  changes  which  they  are  undergoing.* 

Every  part  of  the  earth,  including  air  and  water,  except 
undecomposed  animal  or  vegetable  matters,  is  regarded  as 
mineral. 

The  term  rock,  in  geological  language,  includes  besides  the 
solid  parts  of  the  globe,  the  loose  materials,  such  as  sand, 

*  This  division  is  proposed  by  the  author,  and  is,  like  all  the  othe  rs 
which  have  been  proposed,  imperfect,  and,  in  some  respects,  objec- 
tionable. It  has  the  advantage  of  being  plain  and  convenient:  such  a 
division,  however,  whether  perfect  or  imperfect,  is  not  indispensable  to 
the  successful  study  of  Geology. 


74  SCIENTIFIC    AGRICULTURE. 

gravel,  clay,  soils,  <fec.,  which  constitue  a  part  of  its  crust 
"  Taken  as  a  whole,  the  earth  is  about  five  times  heavier  than 
water,  and  two  and  a  half  times  heavier  than  common  rocks." 
The  density  of  the  earth  increases  from  the  surface  towards 
the  centre.  The  surface  of  the  earth  beneath  the  ocean,  as 
well  as  the  dry  land,  is  elevated  into  hills,  with  plains  and 
Tallies  intervening.  The  mean  depth  of  the  ocean  is  estimated 
at  between  two  and  three  miles;  from  the  phenomena  of  tides, 
the  Atlantic,  in  its  middle  part,  is  supposed  to  be  over  nine 
miles  deep. 

DEFINITION    OF    TERMS. 

Rocks  are  divided  into  two  great  classes,  viz:  stratified  and 
unstratified. 

Stratification  consists  of  the  division  of  a  rock  into  regular 
parallel  planes  or  leaves,  varying  in  thickness  from  that  of  thin 
paper,  to  several  yards.  Strata  are  often  tortuous  and  variable 
in  thickness  in  different  parts  of  the  same  lamina  or  layer; 
"nevertheless,  the  fundamental  idea  of  stratification,  is  that  of 
parallelism  in  the  layers."  "The  term  stratum  is  sometimes 
employed  to  designate  the  whole  mass  of  a  rock,  while  its 
parallel  subdivisions  are  called  beds,  or  layers."  So,  also,  of 
sand,  clay,  gravel,  &c. 

The  term  bed  is  used  to  designate  a  layer  or  mass  of  rock 
more  or  less  irregular,  lenticular  or  wedge  shaped,  lying 
between  the  layers  of  another  rock, — such  as  beds  of  coal, 
gypsum  or  iron. 

Fig.  1. 

-     -     -     -     "Without  lamina. 

-  With  waved  lamina. 

•  Finely  laminated. 

-  Coarsely  laminated. 

-  -     -     Obliquely  laminated 

-  -     -     -  Parallel  lamina. 


GEOLOGY. 


"  A  seam  is  a  thin  layer  of  rock  that  separates  the  beds  or 
strata  of  another  rock,  as  a  seam  of  coal,  limestone,  <fec." 

A  joint  is  a  separation  of  rocks,  both  stratified  and  unstrati- 
fied,  into  masses  of  some  determinate  shape :  joints  are  more 
or  less  parallel,  and  usually  cross  the  beds  obliquely. 

Cleavage  planes  are  divisions  in  rocks,  which  do  not  coincide 
with  those  of  stratification,  lamination  or  joints.  They  are 
supposed  to  result  from  a  crystaline  arrangement  of  the  par- 
ticles of  the  rock. 

Fig   2     Cleavage  Planes. 

d  A  A 


A  A        a   B 

[Fig.  2  exhibits  the  planes  of  stratification,  B,  B, — the  joints,  A,  A,  A, 
A,  and  the  slaty  cleavage,  d,  d.] 

Horizontal  strata  are  those  which  have  little  or  no  inclina  - 
tion,— but  lie  parallel  Fig"  3'  Horizontal  *™** 

with  the  horizon:  this 
position,    however, 
rare,  almost  all  strata  being  more  or  less  inclined. 

The  Dip  of  strata  signifies  the  angle  which  they  form  with 

the  horizon.  Fig.  4.     Dip  and  Outcrop. 

0  utcrop. — When 
strata  are  uncovered 
above  the  surface,  or 
protrude  from  the  side  of  a  hill  so  as  to  be  visible,  they  are 
said  to  crop  out. 

An  Escarpment  is  formed  when  strata  terminate  abruptly, 
so  as  to  form  a  precipice. 


76  SCIENTIFIC    AGRICULTURE. 

A  Fault  in  a  rock  is  the  dislocation  of  strata,  so  that  their 
continuity  is  destroyed,  and  a  series  of  strata  on  one  or  both 
sides  of  the  fracture  are  forced  from  their  original  position, 
and  raised  one  above  another,  or  moved  laterally.  Faults  are 
generally  filled  with  clay,  sand  and  fragments  of  other  rocks. 

A  Gorge  is  a  wide  and  open  fissure  or  fault:  when  still 
wider,  with  sloping  sides  and  rounded  at  the  bottom,  it  is 
called  a  valley. 

Fig.  5.    Dyke. 

A  Dyke  is  a  mass  or  wall  of 
rock  interposed  between  the 
ends  of  a  dislocation,  so  as  to 
break  their  continutity:  dykes 
rarely  send  off  branches. 

Veins  are  portions  of  rocks  smaller  than  dykes,  proceeding 
from  some  large  mass,  and  ramifying  through  a  rock  of  a 
different  kind.  Metallic  veins  were  originally  melted  metals, 
which  were  injected  into  the  fissures  and  crevices  of  rocks  by 
some  subterranean  force. 

Fossil. — This  term  includes  those  petrified  remains  of  plants 
and  animals  which  are  found  in  alluvium,  or  imbedded  in  solid 
rock,  and  constituting  part  of  its  structure. 

Formations. — The  term  formation  is  used  to  designate  a 
group  of  rocks  having  some  character  in  common,  —  either  in 
relation  to  age,  origin  or  composition.  JSvery  formation  con- 
sists of  several  varieties  of  rock,  all  agreeing  in  certain  qualities, 
and  occupying  such  relative  situations  as  to  indicate  that  they 
were  formed  during  the  same  period  and  under  similar  circum- 
stances. Thus  we  speak  of  graywacke  formation,  gneiss  for- 
mation, coal  formation,  &c. 

CLASSIFICATION    OF    ROCKS. 

Many  different  classifications  of  rocks  have  been  proposed, 
none  of  which  is  entirely  unexceptionable :  the  present  state  of 
Geological  science  will  admit  of  our  adopting  any  one  of  them* 


GEOLOGY. 


77 


without  the  risk  of  incurring  much  inaccuracy.  It  is  not 
designed  in  this  treatise  to  give  a  full  classification  of  all  the 
rocks,  with  a  detailed  description  of  their  characters,  but  only 
the  outlines  of  classification,  and  a  brief  description  of  such  as 
are  deemed  most  important  to  our  present  purpose. 

Notwithstanding  the  apparent  discrepancies  among  the 
systems  of  classification,  "  in  all  the  essential  principles,  geolo- 
gists are  nearly  agreed  :  they  all  admit  one  class  to  be  stratified 
and  another  unstratified:  —  one  portion  of  the  stratified  rocks 
to  be  fossiliferous  and  another  portion  not  fossiliferous  :  and 
they  generally  agree  also  as  to  the  extent  of  the  different 
distinct  formations.  Now  these  three  principles  are  all  that 
are  essential  for  classification  ;  and  some  of  the  best  geologists 
limit  themselves  to  these."  —  [Hitchcock.] 

One  very  common  and  natural  classification  of  rocks  is,  into 
two  great  families,  viz  :  stratified  and  unstratified.  We  shall 
give  the  outlines  of  two  others,  viz  :  the  improved  Wernerian 
and  that  of  Mr.  Lyell. 

IMPROVED    WERNERIAN    CLASSIFICATION. 

(  Alluvium, 
ALLUVIAL. 


TERTIARY.     <J  Tertiary  strata. 

ChalTc, 

Green  sand, 

Wealden, 

Oolitic  system, 

Lias, 

New  red  sandstone, 

Coal  formation, 

Carboniferous  limestone, 

Old  red  sandstone. 


SECONDARY. 


TEANSIT.ON. 


Silurian  system, 
ywt 

*7 


PRIMARY. 


78   .  SCIENTIFIC  AGRICULTURE. 

f  Clay  slate, 

Quartz  rock, 

Hornblende  slate, 

Talcose  slate, 
j  Primary  limestone, 

Serpentine, 

Mica  slate, 

Gneiss. 

Alluvium. — If  we  commence  at  the  surface  of  a  soil  which 
has  been  formed  by  the  successive  deposits  of  annual  floods,  or 
the  freshets  of  rivers,  and  descend  to  the  lowest  class  of  rocks, 
viZj — the  primary, — we  shall  pass  through  the  different  classes 
of  rocks  in  the  following  order.  The  first  few  feet,  usually 
less  than  one  hundred,  is  composed  of  vegetable  and  earthy 
matters,  loam,  sand  and  fine  gravel,  deposited  in  horizontal 
beds. 

Drift. — The  second  formation  is  made  up  of  coarse  and  fine 
sand,  gravel,  and.  sometimes  clay,  containing  rounded  masses 
of  rock  called  boulders.  This  mixture  is  often  horizontally 
stratified. 

Tertiary. — The  third  series  is  composed  of  clay,  sand,  gravel 
and  marl,  with  occasional  beds  of  quartzose  and  calcareous 
rock,  which  have  been  deposited  from  water  in  a  quiet  state. 
This  series  also  contains  many  organic  remains :  the  strata  are 
usually  horizontal,  but  sometimes  they  have  a  small  dip. 

Secondary. — The  next  series  below  the  tertiary  is  composed 
mostly  of  solid  rocks :  these  rocks  are  made  up  mainly  of  sand, 
clay  and  pebbles  cemented  together :  these  are  interstratified 
by  organic  remains  and  several  varieties  of  limestone, — they 
usually  dip  at  various  angles.  The  older  fossiliferous  rocks 
included  in  this  series  are  sometimes  called  transition  rocks. 

Primary — Transition. — This  class  includes  both  stratified 
and  unstratified  crystaline  rocks,  which  are  destitute  of  organic 
remains.  The  unstratified  rocks  lie  below  the  stratified  ones 
wherever  they  have  been  found :  hence  it  is  inferred  that  the 
interior  of  the  globe  consists  of  unstratified  crystaline  rocks. 


80  SCIENTIFIC  AGRICULTURE. 

L YELL'S  CLASSIFICATION. 

Mr.  Lyell  comprehends  all  the  various  rocks  which  compose 
the  crust  of  the  earth  in  four  great  classes,  depending  for  their 
distinctive  characters  on  their  origin  and  age.  These  are 
named  as  follows. 

f  AQUEOUS, 
J  VOLCANIC, 
j  PLUTONIC, 
^  METAMORPHIC. 

Aqueous  Rocks. — This  class,  called  also,  the  sedimentary 
rocks,  covers  a  larger  portion  of  the  earth's  surface  than  any 
of  the  other  three  classes.  They  are  stratified,  and  supposed 
to  have  been  deposited  by  water,  both  running  and  quiescent: 
they  contain  fossils,  shells  and  coals. 

Volcanic  Roclcs. — This  class  of  rocks  has  been  produced, 
both  in  ancient  and  modern  times,  by  the  action  of  volcanic 
fires  or  subterranean  heat.  "They  are  for  the  most  part 
unstratified,  and  devoid  of  fossils:"  they  are  more  partially 
distributed  than  aqueous  formations,  at  least  in  respect  to 
horizontal  extension. 

Plutonic  Rocks. — This  class  of  rocks  has  been  formed,  "  at 
great  depths  in  the  earth,  and  they  have  cooled  and  crystalized 
slowly,  under  enormous  pressure,  where  the  contained  gases 
could  not  expand."  They  are  more  crystaline  than  the  others, 
have  no  cavities,  and  contain  no  organic  remains.  They  lie 
below,  and  are  older  than  all  others. 

Metamorphic  Rocks* — These  rocks,  according  to  Mr.  Lyell, 
were  originally  deposited  from  water  in  regular  strata,  and 
afterwards  metamorphosed  or  changed  by  subterranean  heat, 
so  as  to  assume  a  new  and  different  texture.  They  contain  no 
pebbles,  pieces  of  imbedded  rock,  nor  organic  remains,  and  are 
often  crystaline,  as  granite.  They  vary  in  color  and  compo- 

*  This  class  is  considered  as  merely  a  hypothetical  division  by  many 
of  the  best  Geologists. 


GEOLOOT.  81 

sition.  The  degree  of  heat  which  produced  the  change  in 
those  rocks  was  less  intense  than  that  which  produced  the 
plutonic  class,  and  was  doubtless  assisted  by  gaseous  agency. 

We  have  thus  given  a  brief  outline  of  two  systems  of  classi- 
fication, without,  however,  giving  the  reasons  in  favor  of  the 
propriety  of  any  theory  or  classification.  Our  limits  will  not 
admit  of  a  subdivision  of  the  classes  into  orders,  genera  and 
species, — much  other  useful  matter  must  also  be  excluded. 
A  few  of  the  most  important  rocks  and  the  metalloids  have 
been  described,  being  thought  indispensable  to  a  proper  under- 
standing of  the  principles  of  geology  and  the  constitution  of 
soils. 


CHAPTER  II. 


GRANITE. 


GRANITE  is  a  compound  of  three  minerals,  viz:  quartz, 
feldspar  and  mica :  the  different  ingredients  are  sometimes  in 
coarse  crystaline  fragments,  and  in  other  cases  so  fine  as  to 
be  scarcely  distinguishable  by  the  naked  eye.  Granite  is 
most  usually  of  a  whitish  or  flesh  color, — it  has,  however,  other 
tints.  Feldspar  predominates  in  the  composition  of  granite, 
while  the  mica  is  in  the  smallest  quantity.  "These  three 
minerals  are  united  in  what  is  termed  confused  crystallization: 
that  is,  there  is  no  regular  arrangement  of  the  crystals  in 
granite  as  in  gneiss."  The  coarse  grained  granites  contain 
the  most  interesting  specimens  of  simple  minerals,  while  the 
finer  kinds  are  best  for  architectural  purposes. 

Granite  often  preserves  a  uniform  character  through  a  great 
extent  of  country,  forming  rounded  hills:  it  is  sometimes, 
though  not  generally,  subdivided  by  fissures  into  masses  of  a 
cuboidal  and  columnar  form.  Where  it  is  naked  at  the 
surface,  and  exposed  to  atmospheric  changes  and  action,  it  is 
in  a  crumbling  state,  and  covered  with  a  scanty  vegetation.  It 
is  remarked  by  Lyell,  that  all  granitic  rocks  are  frequently 
observed  to  contain  metals,  at  or  near  their  junction  with 
stratified  rocks. 

Granite  is  supposed  to  be  the  oldest,  most  abundant  and 
important  of  all  the  unstratified  rocks.  There  are  several 


GEOLOGY.  83 

varieties  of  granite,  viz:  graphic  granite,  syenitic  granite, 
talcose  granite,  porphyritic  granite,  eurite  and  pegmatite: 
these  varieties  have  various  proportions  of  each  element,  and 
also  various  colors  and  crystaline  arrangement. 

SYENITE. 

Syenite  is  composed  of  quartz,  feldspar  and  hornblende :  it 
is  sometimes  called  syenitic  granite, — it  has  received  this  name 
from  the  ancient  quarries  at  Syene  in  Egypt.  It  has  the 
appearance  of  granite,  but  its  composition  is  different,  horn- 
blende being  substituted  for  the  mica  in  granite.  Syenite, 
according  to  Lyell,  frequently  loses  its  quartz  and  passes  insen- 
sibly into  syenitic  greenstone. 

PORPHYRY. 

Rocks  of  a  homogeneous,  compact  structure,  containing  some 
other  crystaline  mineral,  of  the  same  age  with  the  base,  are 
called  porphyry.  The  base,  or  principal  mass  of  the  rock,  may 
be  greenstone,  claystone,  basalt,  or  other  rock  containing  crys- 
tals of  feldspar,  augite,  olivine,  <fec. 

"  True  classical  porphyry,  [says  Dr.  Hitchcock,]  such  as  was 
most  commonly  employed  by  the  ancients,  has  a  base  of  com- 
pact feldspar,  with  embedded  crystals  of  feldspar."  The  term 
porphyry  is  indefinite,  and  does  not  belong  to  any  particular 
rock.  The  term  is  of  Greek  origin,  and  signifies  purple, — but 
this  rock  is  of  a  variety  of  colors,  and  is  the  hardest  and  most 
durable  of  all  rocks. 

GREENSTOXE. 

This  is  a  granular  rock  composed  of  feldspar  and  hornblende ; 
the  felsdpar  is  imperfectly  crystalized :  greenstone  sometimes 
contains  augite  and  iron  also.  The  hornblende  predominates 
in  quantity  over  the  other  ingredients. 

TRACHYTE. 

Trachyte  is  a  porphyritic  rock  of  a  grayish  or  whitish  color, 


84  SCIENTIFIC    AGRICULTURE* 

composed  principally  of  glassy  feldspar,  containing  also  crystals 
of  feldspar,  mica,  hornblende,  and  sometimes  iron.  It  is  rough 
and  harsh  to  the  touch, — hence  its  name  from  the  Greek  word 
trachus,  (rough:)  it  occurs  in  vast  quantities  in  Europe  and 
South  America,  in  volcanic  regions,  but  is  not  found  in  the 
United  States. 

BASALT. 

"  Basalt  consists  of  an  intimate  mixture  of  augite,  felspar 
and  iron,  to  which  a  mineral  of  an  olive  green  color  called 
olivinc,  is  often  superadded  in  distinct  grains  or  nondular 
masses."  The  iron  is  usually  magnetic,  and  is  sometimes 
accompanied  by  the  metal  titanium,  hence  the  name,  "titani- 
ferous  iron."  Augite  is  the  predominant  element  in  this  rock: 
basatt  presses  insensibly  into  most  other  varieties  of  trap  rock. 
True  basalt  does  not  occur  in  the  United  States. 

AMYGDALOID. 

Any  rock  containing  almond  shaped  pieces  of  some  other 
mineral,  as  quartz,  chalcedony,  agate,  calcareous  spar,  or  zeo- 
lite, may  be  denominated  amygdaloid:  the  base  may  be  wacke, 
basalt,  greenstone,  or  any  other  trap  rock.  Some  amygdaloid 
rocks  have  the  almond  shaped  cells  or  cavities,  which  are 
empty,  and  glazed  on  their  sides  by  a  glassy  coating,  showing 
their  igneous  origin. 

SERPENTINE. 

This  is  a  greenish  colored  rock,  containing,  according  to  Dr. 
Hitchcock,  40  per  cent,  of  magnesia, — it  is  a  hydrated  silicate 
of  magnesia.  Serpentine  sometimes  contains  diallage,  steatite, 
talc,  and  some  iron.  It  is  classed  by  most  authors  among 
unstratified  rocks.  Comparatively  it  is  not  a  rock  of  great 
extent:  it  is  often  associated  with  talcose  slate. 

LAVA. 

Under  the  term  lava,  are   embraced  all   the  varieties  of 


GEOLOGY.  85 

melted  matter  thrown  out  by  volcanoes:  these  are  composed 
almos't  entirely  of  feldspar  and  augite.  Some  lavas  are  por- 
phrytic,  and  contain  imperfect  crystals,  "derived  from  some 
older  rocks,  in  which  the  crystals  pre-existed,  but  were  not 
melted,  as  being  more  infusible  in  their  nature." 

When  lava  is  cooled  in  the  open  air,  it  is  light,  porous  and 
spongy,  and  floats  on  water,  as  is  the  case  with  pumice  stone ; 
but  when  cooled  under  great  pressure,  at  considerable  depths 
below  the  surface,  solid  rock  is  the  result 

There  are  several  varieties  of  lava,  varying  in  composition, 
and  also  of  different  colors,  as  gray,  whitish,  greenish  and  dark: 
fragments  of  granite  and  other  rocks,  —  several  metals  and 
gases,  water,  sulphur,  mud,  glass,  and  various  salts  and  acids, 
are  ejected  from  the  craters  of  active  volcanoes. 
GNEISS. 

Gneiss  is  composed  of  quartz,  feldspar  and  mica,  and  some 
specimens  contain  hornblende.  This  rock  is  essentially  the 
same  as  granite,  except  it  is  stratified.  The  laminated  struc- 
ture becomes  obscure  where  the  gneiss  passes  into  granite: 
its  stratification  is  remarkably  regular  in  some  specimens,  and 
in  others  tortuous  and  irregular.  This  rock  is  said  to  be  very 
extensive  in  the  United  States,  particularly  in  New  England. 
QUARTZ. 

This  rock  is  composed  either  of  an  aggregate  of  fine  grains 
or  crystals  compacted  together,  or  of  a  solid  homogeneous 
mass  of  quartz,  sometimes  containing  feldspar,  mica,  horn- 
blende, talc  or  clay  slate.  "  In  these  compound  varieties,  [says 
Hitchcock,]  the  stratification  is  remarkably  regular;  but  in 
pure  granular  quartz,  it  is  often  difficult  to  discover  the  planes 
of  stratification." 

It  is  alternated  or  interstratified  with  all  the  primary  rocks, 
in  which  case  its  structure  is  regular.  Some  quartz  is  capable 
of  sustaining  a  powerful  heat  without  cracking  or  other 
change, — hence  it  makes  an  excellent  fire  stone. 

8 


86  SCIENTIFIC    AGRICULTURE. 

HORNBLENDE    SLATE. 

Hornblende  predominates  in  this  rock,  over  the  various 
quantities  of  quartz,  feldspar  and  mica  which  it  sometimes 
contains. '  When  it  contains  much  feldspar,  it  is  not  slaty,  but 
resembles  greenstone.  It  is  of  a  dark  color,  commonly  asso- 
ciated with,  and  passes  insensibly  into  clay  slate,  mica  slate 
and  gneiss. 

CLAY   SLATE. 

This  rock  is  composed  mostly  of  fine  clay,  and  is  usually 
more  or  less  dark  and  shining  from  the  mixture  of  chlorite  and 
black  lead  which  it  contains.  "  It  may  [says  Lyell,]  consist  of 
the  ingredients  of  gneiss,  or  of  an  extremely  fine  mixture  of 
mica  and  quartz,  or  talc  and  quartz."  It  passes  insensibly 
into  mica  slate,  talcose  slate,  or  hornblende  slate :  on  the  other 
hand  it  passes  into  unconsolidated  clay. 

Clay  slate  is  the  kind  used  for  roofing:  it  varies  in  color 
according  to  its  composition,  from  greenish  or  bluish  gray  to 
lead  color.  This  rock,  as  well  as  the  following,  is  used  for 
whetstones:  the  best  hones  are  compact  feldspar,  and  are 
erroneously  supposed  to  be  petrified  wood. 

MICA    SLATE. 

This  rock  is  a  compound  of  quartz  and  mica,  the  mica  being 
in  the  greatest  quantity.  This  is  one  of  the  most  common 
and  abundant  of  the  stratified  rocks.  It  sometimes  contains 
beautiful  twelve-sided  crystals  of  garnet  in  considerable  abun- 
dance :  beds  of  pure  quartz  also  occur  in  this  rock. 

PRIMARY    LIMESTONE. 

This  rock  is  sometimes  in  thick  beds  of  white,  bluish, 
greenish  or  gray  granular  marble,  such  as  is  used  in  sculpture : 
it  sometimes  contains,  mica,  quartz,  hornblende,  feldspar  and 
talc.  It  is  both  stratified  and  unstratified;  sometimes  being  in 
thick  beds  without  any  marks  of  mechanical  arrangement,  and 


GEOLOGY. 


87 


at  others  it  is  in  laminated  leaves  or  scales  like  slate,  of  various 
thickness. 

TALCOSE  SLATE. 

Talc  is  the  principal  ingredient  in  this  variety  of  slate, — it 
is  sometimes  in  a  pure  state  and  sometimes  mixed  with  quartz, 
feldspar,  mica,  hornblende  or  limestone :  it  is  a  softish  stone, 
valuable  for  building  purposes.  There  are  several  varieties. 

Composition  of  Feldspar. 
Silica,    -  -  65.21 

Alumina,  -  -     18.13 

Potash,  16.66 

100.00 

Composition  of  Basaltic  Hornblende. 
Silica,   -  42.24 

Alumina,  -  -     13.92 

Lime,    -  12.24 

Magnesia,  -     13.74 

Protoxide  of  Iron,  -  14.59 

Oxide  of  Manganese,  -         -        -       p.  3  3 


Composition  of  Mica. 
Silica,    - 

Alumina,  -  - 

Protoxide  of  Iron,  - 
Potash,     - 
Oxide  of  Magnesia, 
Fluoric  Aeid,     - 
Water,  - 

CHALK. 


97.06 

46.10 
31.60 
8.65 
8.39 
1.40 
1.12 
1.00 

98.26 


Chalk  is  similar  in  composition  to  carbonate  of  lime,  viz: 


88  SCIENTIFIC    AGRICULTURE. 

carbonic  acid,  44, — lime,  56, — 100.  It  is  a  pulverizable  rock, 
of  several  varieties,  which  have  resulted  from  the  impurities 
which  were  deposited  with  it.  The  chalk  beds  contain  great 
quantities  of  flint,  which  is  dispersed  through  them  in  small 
masses.  Chalk  also  contains  organic  remains:  it  is  a  durable 
building  stone,  and  is  used  for  docks,  &c. ;  some  ancient 
buildings  are  of  chalk :  no  chalk  has  been  found  in  America. 

ROCK  SALT. 

This  cannot  be  considered  a  rock,  but  yet  it  occurs  in  vast 
beds,  and  in  connection  with  rocks,  at  great  depths  in  the 
earth.  In  its  pure  form  it  is  a  transparent  crystaline  salt, 
having  the  appearance  of  flint  glass :  the  impure  specimens  are 
reddish  or  bluish,  and  mixed  with  sulphate  of  soda  and  muriate 
of  magnesia.  Its  origin  is  not  exactly  known ;  it  is  supposed, 
however,  to  have  resulted  from  the  evaporation  of  sea  water. 
It  is  found  in  Spain,  Poland,  Hungaiy,  Germany,  and  in  some 
parts  of  Asia  and  America. 

COAL 

Mineral  or  fossil  coal  is  of  several  varieties,  differing  in 
density  and  weight,  and  of  a  dark  color,  varying  from  brown  to 
jet  black.  It  is  composed  of  carbon  and  bitumen,  and  usually 
contains  some  other  matters.  Coal  is  undoubtedly  of  vegetable 
origin :  as  evidence  of  this,  the  organic  structure  of  coal  can  be 
seen  in  some  specimens  so  distinctly  that  about  three  hundred 
species  of  plants  have  been  discovered  in  the  various  kinds.  It 
contains  also  many  species  of  fossil  animals. 

Coal  beds  vary  in  thickness,  from  a  few  feet  to  three  thou- 
sand or  more, — and  are  often  several  miles  in  length.  The 
manner  in  which  such  immense  masses  of  vegetable  matter 
have  accumulated  during  the  lapse  of  ages,  may  be  conceived 
by  reference  to  a  single  example. 

"According  to  Bringier,  the  quantity  of  timber  which 
drifted  into  the  Atchafalaya,  an  arm  of  the  Mississippi,  during 


GEOLOGY. 


89 


an  overflow  in  1812,  amounted  to  8,000  cubic  feet  per  minute. 
The  raft  thus  collected  at  the  mouth  of  the  Red  River,  is  sixty 
miles  long*,  and  in  some  parts  fifteen  miles  wide."  The  quan- 
tity which  descends  the  Mississippi  in  a  few  years  might 
furnish  sufficient  matter  for  the  largest  coal  bed  known. 

The  varieties  of  coal  are  brown  coal,  or  lignite, — bituminous 
coal, — anthracite  coal,  and  graphite,  or  black  lead :  this  consists 
of  carbon  and  iron, — and,  according  to  Dr.  Hitchcock,  "appears 
to  be  anthracite  which  has  undergone  a  still  further  minerali- 
zation." All  these  varieties  of  coal  occur  in  seams  or  beds, 
interstratified  by  sandstone  and  shales:  brown  coal  is  found 
mostly  in  the  tertiary,  bituminous  in  the  secondary  series,  and 
also  with  new  red  sandstone  and  clay. 

Anthracite  is  found  in  graywacke,  mica  slate,  limestone, 
gneiss,  plastic  clay,  and  almost  all  stratified  rocks. 


[Fig.  7  is  a  sketch  of  the  great  coal  basin  of  South  Wales,  in  Great 
Britain, — which  contains  seventy-three  beds  of  coal,  whose  united 
thickness  is  ninety-three  feet.] — Hitchcock. 

*8 


PART    III. 


BOTANY. 


CHAPTER  I. 

BOTANY  is  that  branch  of  natural  science  which  investigates 
the  nature  and  character  of,  and  includes  all  knowledge  in 
relation  to  the  vegetable  kingdom.  It  treats  of  the  structure, 
habits,  locality,  uses,  classification  and  nomenclature  of  every 
species  of  plant  known  on  the  globe. 

Botany  is  divided,  for  the  sake  of  convenience  and  method, 
into  PHYSIOLOGICAL  and  SYSTEMATIC:  Physiological  Botany 
resolves  itself  into  Anatomy,  Morphology  and  Vegetable  Phy- 
siology. 

Anatomy  treats  of  the  organic  structure  and  relations  of  all 
the  various  parts  of  plants. 

Morphology  treats  of  their  form,  symmetry,  and  arrange- 
ment. 

Vegetable  physiology  treats  of  all  the  phenomena  of  the 
vital  functions,  as  absorption,  exhalation,  digestion,  respiration, 
circulation,  germination,  &c. 

Systematic  botany  is  divided  into  botanical  classification, 
special  descriptive  botany,  glossology,  and  geographical  botany. 


92  SCIENTIFIC    AGRICULTURE. 

Classification  treats  of  the  proper  grouping  and  arrangement 
of  plants  according  to  their  natural  affinities  and  characters. 

Special  descriptive  botany  consists  in  applying  correctly  the 
generic  and  specific  botanical  names  to  parts. 

Glossology  consists  in  the  explanation  and  application  of 
names  to  all  the  various  organs  of  plants. 

Geographical  botany  treats  of  the  climate,  country,  zone 
and  locality  to  which  the  various  species  belong. 

Finally,  botany  comprehends,  in  its  most  extended  sense,  a 
knowledge  of  the  relations  of  the  vegetable  kingdom  to  other 
departments  of  natural  objects,  and  the  development  of  the 
limitless  resources  of  this  part  of  the  CREATOR'S  vast  plan  for 
the  sustenance  and  happiness  of  his  creatures.  « 

PRIMARY    DIVISIONS    OF    PLANTS. 

The  vegetable  kingdom  is  divided  into  two  great  natural 
families,  viz :  PHENOGAMIA,  or  that  division  which  includes  all 
flowering  plants,  and  CRYPTOGAMIA,  or  that  which  includes  all 
floioerless  plants. 

These  two  divisions  are  further  distinguished  by  the  dif- 
ference in  their  elementary  structure.  The  phenogamous,  or 
flowering  plants,  abound  with  the  woody  and  vascular  tissues ; 
while  the  cryptogamous,  or  flowerless  plants,  consist  almost 
entirely  of  the  cellular  tissue.  The  phenogamia  produce  seeds 
having  the  cotyledon  and  embryo, —  while  the  cryptogamia 
produce  minute  organs  called  spores,  having  no  such  distinc- 
tion of  organs.  The  phenogamia  are  therefore  called  cotyle- 
donous,  and  the  cryptogamia,  acotyledonous.  In  the  former, 
also,  we  find  a  system  of  compound  organs,  regularly  and  suc- 
cessively developed,  in  the  order  of  root,  stem,  leaf,  flower  and 
seed, — while  the  latter  appear  to  be  "simple  expansions  of 
cellular  tissue,  without  order,  symmetry  or  proportion." 

CLASSIFICATION   OF   PLANTS. 

All  natural  sciences  classify  their  respective  objects  under 


BOTANY.  93 

certain  fundamental  divisions.  The  first  of  these  divisions  is 
into  CLASSES, — the  second  divides  classes  into  ORDERS, — the 
third  divides  orders  into  GENERA, — the  fourth  divides  genera 
into  SPECIES,  and  these  are  again  divided  into  varieties. 

The  number  now  known  on  the  whole  earth,  is  between 
80,000  and  100,000  distinct  species  of  plants.  The  classifica- 
tion of  plants,  and  all  other  natural  objects,  is  founded  on  the 
resemblance  and  differences,  in  some  one  or  more  points,  of  the 
individuals  of  each  class,  order,  <fec. 

A  CLASS,  in  natural  history,  comprises  an  assemblage  of 
objects  or  individuals,  having  one  or  more  common  charac- 
teristics. Thus  the  whale,  the  hog  and  the  cow  all  belong  to 
the  class  mammalia, — because  they  all  have  red  blood,  breathe 
by  means  of  lungs,  and  nourish  their  young  by  means  of  milk : 
the  whitewood,  rose  and  locust  all  belong  to  the  division  phe- 
nogainia  and  class  angeiosperma, — because  they  all  produce 
flowers  and  woody  stems,  and  bear  fruit  in  capsular  vessels. 

An  ORDER  is  a  subdivision  of  a  class,  and  divides  objects 
into  groups,  which  are  distinguished  by  more  minute  and 
peculiar  points  of  resemblance  than  those  on  which  a  class  is 
based,  but  still  possessing  all  the  peculiar  characteristics  of 
that  class.  The  lion,  tiger,  dog  and  cat,  all  belong  to  the  class 
mammalia  and  order  carnivora,  because  they  live,  in  their 
native  state,  on  flesh:  the  water-cress,  turnip  and  mustard  all 
belong  to  the  order  cruel/era,  because  they  all  produce  flowers 
having  four  petals,  arranged  in  the  form  of  a  cross. 

"  A  GENUS  is  an  assemblage  of  species  with  more  points  of 
agreement  than  difference,  and  more  closely  resembling  each 
other  than  they  resemble  any  species  of  other  groups."  This 
is  a  subdivision  of  an  order.  The  dog,  wolf,  lion  and  cat,  all 
belong  to  the  same  order, — but,  on  account  of  certain  dif- 
ferences, the  lion  and  cat  belong  to  one  genus,  and  the  dog 
and  wolf  to  another:  the  apple,  cherry,  rose  and  almond,  all 


94  SCIENTIFIC    AGRICULTURE. 

belong  to  the  order  rosacea,  but  they  belong  to  different 
genera,  according  to  some  peculiarity  in  the  organs  of  each. 

A  SPECIES  "embraces  all  such  individuals  as  may  have 
originated  from  a  common  stock:  such  individuals  bear  an 
essential  resemblance  to  each  other,  as  well  as  to  their  common 
parent,  in  all  their  parts."  This  is  a  subdivision  of  a  genus. 
The  white  and  red  clover  both  belong  to  the  genus  trifolium; 
but  they  differ  in  some  minor  points  sufficiently  to  place  them 
in  different  species. 

A  variety  is  a  subdivision  of  a  species,  and  is  the  last 
distinction  made  in  any  system  of  classification :  varieties  in  the 
vegetable  kingdom  occur  principally  in  the  cultivated  species; 
they  depend  only  upon  slight  differences,  as,  for  instance,  the 
same  apple  tree,  rose  bush,  or  potato  vine,  may  produce  fruit, 
tubers  and  flowers  of  different  colors,  but  still  alike  in  all  essen- 
tial characteristics. 

We  see  through  the  whole  vegetable  kingdom,  a  most 
marked  analogy  and  connection,  from  the  minutest  organized 
microscopic  plant,  to  the  largest  forest  tree:  there  are  also 
differences  so  obvious  that  there  can  be  no  doubt  of  the  pro- 
priety of  arranging  them  into  different  groups  according  to 
their  peculiar  characters. 

ELEMENTARY    ORGANS    OF    PLANTS. 

The  most  simple  and  elementary  form  of  a  plant  is  that  of 
the  embryo,  which  is  produced  by,  and  contained  in  the  seed. 
This  consists  of  two  parts,  viz :  the  plumula  and  radicle.  The 
plumula  is  the  part  which  is  afterwards  developed  into  the 
ascending  part  of  the  plant,  the  stem,  branches  and  leaves- 
The  radicle  is  that  which  becomes  the  root,  and  descends  into 
the  earth  in  search  of  food  and  moisture.  The  ascending  part 
of  the  young  plant  is  at  first  merely  a  minute  growing  point, 
enveloped  in  delicate  rudimental  leaves,  which  constitute  a 
lud. 


95 


fed  c 

[Fig.  1, — Forms  of  tissue;  a,  cutting  of  elder  pith,  cellular;  b,  cells 
from  the  gritty  centre  of  the  pear;  c,  from  the  stone  of  the  plum — both 
strengthened  by  solid  matter;  d,  woody  fibre;  e,  spiral  vessel  with  a 
single  fibre  partly  drawn  out;  f,  vessel  with  a  quadruple  fibre. — Wood.~\ 

The  several  elementary  structures  of  which  the  various 
parts  of  plants  are  made  up,  are  called  elementary  tissues: 
they  are  five  in  number,  viz:  the  cellular,  woody,  vasiform, 
vascular,  and  laticiferous.  The  chemical  elements  of  which 
these  tissues  are  composed,  are  enumerated  and  described  in 
works  on  chemistry. 

Cellular  tissue  is  composed  of  a  series  of  minute  cells 
attached  together,  and  having  a  more  or  less  regular  form. 
Fig.  1,  a. 

Woody  tissue  consists  of  minute  tubes,  tapering  to  a  point 
at  both  ends,  and  adhering  by  their  sides,  the  end  of  one  tube 
overlapping  that  of  another  so  as  to"  form  continuous  threads. 
Fig.  1,  d. 

The  vasiform  tissue  consists  of  tubes,  large  enough  to  be 
seen  by  the  naked  eye  in  some  plants, — as,  for  example,  in  a 
transverse  section  of  the  oak.  In  some  plants  these  tubes  are 
jointed,  or  divided  by  partitions,  and  in  others  they  arc  con- 
tinuous. It  is  through  these  that  the  sap  rises,  and  they  are 
the  largest  vessels  in  the  vegetable  organization.  Fig.  2,  a. 
Vascular  tissue  consists  of  spiral  vessels,  resembling  some- 


96 


SCIENTIFIC    AGRICULTURE. 


what  the  woody  fibre;  they  contain  air,  and  their  internal 
structure  differs  in  various  plants.  Fig.  2,  b. 

The  laticiferous  tissue  is  that  through  which  is  circulated 
the  latex,  or  nutricious  sap.  It  consists  of  minute,  irregular 
branching  tubes  opening  into  each  other,  and  situated  mostly 
in  the  bark  and  under  side  of  the  leaves.  Fig.  2,  c. 

The  epidermis,  or  outside  bark,  is  formed  of  celluar  tissue, 
and  envelopes  the  entire  plant,  except  the  stigma  of  the  flower, 
and  the  spongioles  of  the  roots.  In  plants  whose  bark  is  rough 
and  ragged,  as  in  the  walnut  and  oak,  it  is  not  distinguishable. 

The  delicate  membrane  which  may  be  stripped  from  the 
iris,  or  house  leek,  is  the  epidermis ;  this  covering  of  plants  is 
perforated  by  minute  orifices  or  mouths,  which  open  and  close 
by  the  presence  or  absence  of  light  The  epidermis  and  leaves 
have  several  appendages,  as  glands,  hairs,  prickles,  thorns* 
receptacles  and  stings,  which  it  is  not  necessary  to  describe  in 
this  treatise. 

Fig.  2. 


[Fig.  2,—  Fornn  of  tissue,  &c.;  a,  annular  ducts;  b,  spiral  and  annu- 
lar at  intervals;  c,  laticiferous  tissues;  e,  stomata  of  iris,  vertical  section; 
d,  d,  green  cells  at  the  orifice;  f,  f,  cells  of  the  parenchyma;  e,  air  cham- 
ber; g,  g,  epidermis  and  stomata  of  yucca;  h.  stomata  closed;  the  dots 
represent  small  luminous  bodies  in  the  cells. —  Wood.~\ 


CHAPTER  II. 


ORGANS  AND  STRUCTURE  OF  THE  FLOWER. 

TIIE  essential  organs  of  a  flower  are  three,  viz :  the  stamens, 
the  pistils,  and  the  receptacle.  These  are  all  the  parts  neces- 
sary to  the  perfection  of  the  seed, — they  therefore  constitute  a 
perfect  flower:  to  these,  however,  is  added  in  most  flowers, 
the  perianth,  consisting  of  the  calyx  and  corrolla. 

The  STAMENS  are  slender,  thread-like  organs  within  the 
"flower"  or  perianth,  around  the  pistils:  their  most  common 
number  is  five :  but  this  varies  from  one  to  a  hundred.  Their 
office  is  said  to  be  the  fertilization  of  the  seed. 

The  PISTILS  are  usually  slender,  larger  than  the  stamens, 
and  occupy  the  centre  of  the  flower :  "  they  are  destined  to 
bear  the  seed."  They  are  sometimes  numerous,  but  in  many 
cases  there  is  only  a  single  one. 

The  RECEPTACLE  is  placed  at  the  end  of  the  flower  stalk,  and 
constitutes  the  basis  upon  which  the  organs  of  fructification  are 
usually  placed,  in  such  manner  as  to  encircle  it. 
Fig.  3.        The  CORROLLA  is  the  interior  Fi£-  ••' 

i part  of  the  perianth,  consisting 
kof  one  or  more  circles  of  colored 
leaves  of  various  hues  and  deli- 
cate texture,  situated  upon  the 
receptacle :  these  leaves  are  called 
petals,  (Fig.  4,  a,  a,) — and  they  may  be 


98 


SCIENTIFIC    AGRICULTURE. 


united  at  the  edges,  constituting  a  bell-form  flower,  (Fig. 3,) 
or  they  may  be  separate,  constituting  a  wheel-form  flower. 
Fig.  e. 

Tig.  4. 

a 


The  CALYX  is  the  external  part  of  the 
perianth,  consisting  of  a  circle  of  leaves, 
the  same  in  number  as  those  of  the 
corrolla,  in  some  cases  distinct,  and  in 
others  united:  they  are  usually  green: 
these  leaves  are  called  sepals.  Fig.  5,  a. 

We  see  now,  that  a  complete  flower  is 
made  up  of  four  regular  sets  of  organs, 
viz :  the  stamens,  pistils,  receptacle  and 
perianth:  these  organs  are  arranged  in 
concsntric  whorls,  or  rings:  some  of  them  may  be  absent,  or 
suppressed,  some  superfluous  ones  may  be  developed  and  some 


BOTANY. 


09 


degenerated  into  those  of  a  different  set,  as  petals  into  stamens, 
flowers  into  leafy  branches,  &c. 

The  stamen  consists  of  three  distinct  parts,  viz:  the  filament, 
(Fig.  6,  a,)  the  anther,  (Fig.  6,  b)  and  the  pollen.     The  filament 
Fis>  6-  is  the  thread-like  part  which  sup- 

ports the  anther  at  its  summit: 
the  pollen  is  a  fine  yellow  dust 
of  various  forms  contained  within 
the  cells  of  the  anther,  until  dis- 
charged through  its  pores  into 
the  air. 

The  pistil  consists  also  of  three 
parts,  viz:  the  ovary,  the  style, 
and  the  stigma. 

The  ovary  is  the  base  of  the 
pistil  which  contains  the  young 
seeds,  and  which  ultimately  be- 
comes the  fruit     Fig.  6,  d. 
The  style  is  a  prolonged  column  arising  from  the  ovary,  and 
supporting  the  stigma  at  its  top.     Fig.  6,  e. 

The  stigma  is  the  upper  extremity  of  the  style,  usually  of  a 
globular  form:  ii  may  be  either  simple  or  compound,  according 
to  the  structure  of  the  ovary  and  style.  Fig  6,  f. 

The  ovules  are  minute  globular  bodies  in  the  cells  of  the 
ovary,  which  become  the  seeds  of  the  matured  fruit 

The  placenta  is  a  fleshy  ridge  within  the  cells  of  the  ovary, 
from  which  the  ovules  are  developed,  and  to  which  they  are 
attached. 

There  are  several  other  secondary  and  minute  parts,  be- 
longing to  the  flower,  which  it  is  not  necessary  or  practicable 
to  describe  here,  as  it  would  only  burthen  the  memory  with 
technical  terms  which  would  convey  but  little  useful  know- 
ledge. 


100 


SCIENTIFIC  AGRICULTURE. 


Fig.  7. 


THE    FRUIT. 

The  ultimate  object  of  the  whole  vegetable  organization 
appears  to  be  the  production  of  fruit;  which  is  the  agent 
through  which  the  reproduction  of  the  species  is  accomplished. 
After  the  seed  is  perfected  in  annual  plants,  they  soon  wither 
and  die :  the  flower  always  precedes  the  fruit,  and  is  neces- 
sary to  its  development  and  perfection.  The  fruit  consists  of 
two  parts,  viz:  &e pericarp  and  the  seed,  or  the  seed-covering 
and  the  seed:  the  pericarp  is  wanting  in  some  plants,  but  the 
seed  is  essential  in  all.  In  the  coniferous  plants,  as  the  pine, 
spruce,  &c.,  the  seed  is  naked  and  destitute  of  the  pericarp. 

The  PERICARP  is  the  part  which  envelops 
the  seed,  whatever  be  its  substance  or  struc- 
ture. Fig.  7.  In  the  peach  and  plum,  this  is 
a  fleshy,  pulpy  substance, — in  the  oak  and 
FiS'  8-  walnut,  a  dense  hard  shell :  (fig.  8.) 
thus  the  structure  and  composi- 
tion of  the  pericarp  varies  in  dif- 
ferent plants,  from  a  soft  watery 
pulp  to  a  dense  shell.  The  pro- 
cess of  the  ripening  of  fruit  con- 
sists of  certain  chemical  changes  produced 
by  the  action  of  light,  heat  and  air,  and 
perhaps  other  agents.  Pericarps  have 
received  specific  names,  according  to  their 

Fig.  9.  form  and  structure:  that  of  the  pea  and  bean 
is  called  a  pod, — that  of  the  walnut  and  but- 
ternut is  called  a  nut, — that  of  the  apple  and 
pear,  a  pome, — that  of  the  currant  and  whor- 
tleberry, a  berry,  &c.  Fig.  9. 

This  figure  represents  the  pericarp,  or  seed 
capsule  of  the  cenothera. 


BOTANY.  101 

THE    SEED. 

The  seed  contains  the  rudiments  of  a  new  plant,  and  is  the 
final  product  of  all  the  complicated  and  beautiful  processes  of 
vegetation.  The  essential  parts  of  the  seed  are,  the  integu- 
ment a,  the  albumen  and  the  embryo. 

The  integuments  are  composed  of  several  distinct  layers, 
which  constitute  the  immediate  coverings  of  the  other  parts. 

The  albumen  lies  next  to  the  integuments,  constituting  the 
principal  bulk  of  some  seeds ;  it  is  a  whitish  substance,  com- 
posed mainly  of  starch,  which,  by  the  chemical  changes  which 
it  undergoes  during  the  process  of  germination,  serves  to 
nourish  the  embryo  plant. 

The  embryo  comprises  all  the  rudiments  of  the  new  plant: 
it  consists  of  three  parts,  viz :  the  radicle,  the  plumule,  and  the 
cotyledon. 

The  radicle  is  the  part  which  forms  the  root, — the  plumule 
Fig.  10.  forms  the  ascending  portion  of  the  plant, — 

the  cotyledon  is  the  bulky  part  of  seeds,  and 
forms  the  first  leaves  of  young  plants,  which 
lin  the    garden  bean,  cucumber,  &c.,  are 
I  thick,  fleshy  and  oval,  when  they  first  rise 
above  the  surface  of  the  ground:   these 
!  support  the  plant  and  perform  the  function 
of  leaves  until  the  proper  leaves  are  formed. 

[This  figure  shows  an  embryo  with  its  plumule 
and  radicle  developed  from  the  cotyledon:  a,  radi- 
cle; b,  plumule;  c,  cotyledon.] 

GERMINATION    OF    SEEDS. 

Germination  consists  of  the  first  chemical  changes  and  vital 
action,  which  take  place  when  a  new  plant  is  about  to  be 
produced. 

"  When  the  seed  is  planted  in  a  moist  soil,  at  a  moderate 
temperature,  the  integuments  gradually  absorb  water,  soften 

*9 


102 


SCIENTIFIC    AGRICULTURE. 


and  expand.  The  water  is  decomposed,  its  oxygen  combines 
with  the  carbon  of  the  starch  which  has  been  stored  up  in  the 
tissues.  Thus,  losing  a  part  of  its  carbon,  the  starch  is  con- 
verted into  sugar  for  the  nourishment  of  the  embryo,  which  now 
begins  to  dilate  and  develop  its  parts.  Soon  the  integuments 
burst,  the  radicle  descends,  seeking  the  damp  and  dark  bosom 
of  the  earth,  and  the  plumule  rises  with  expanding  leaves,  to 
the  air  and  light.  The  conditions  requisite  for  the  germination 
of  the  seed  are,  heat,  moisture,  oxygen,  air  and  darkness." 

[Wood. 

Fig.  A. 


[Fig,  A.  This  cut  represents  a  young  dicotyledonous  plant,  with  its 
radicle,  a,  developed;  its  cotyledons,  c,  c,  appear  in  the  form  of  large 
succulent  leaves;  the  plumule  is  just  appearing  as  a  minute  point 
between  the  cotyledon*.] 

THE    ROOT. 

The  root  constitutes  the  basis  of  the  plant :  it  serves  two 
purposes  in  the  vegetable  economy,  —  first  to  fix  the  plant 


BOTANY. 


103 


mechanically  in  the  soil  and  retain  it  in  its  position, — secondly 
to  absorb  from  the  soil  those  inorganic  elements  which  are 
necessary  for  its  food.  The  general  direction  of  the  root  is 
downwards ;  but  the  roots  of  various  plants  grow  at  all  angles 
from  the  horizontal  to  the  perpendicular :  the  principal  perpen- 
dicular axis  is  called  the  tap  root.  The  number  and  extent  of 
the  roots  must  correspond  with  those  of  the  stalk  and  leaves 
of  the  plants,  in  order  to  supply  their  demand  of  food  from  the 
soil. 

Roots  do  not  usually  extend  to  great  depths,  but  keep 
within  the  limit  of  that  portion  of  soil  which  supplies  their 
proper  nutriment.  Roots  are  distinguished  from  stems  and 
branches  by  the  absence  of  stomata,  buds  and  pith, — and  by 
the  presence  of  absorbing  fibres. 

The  stock,  or  main  body  of  the  root,  sends  off  i\\Q  fibrils,  or 
minute,  slender  branches  of  the  root, — the  delicate,  tender 
extremities  of  the  fibrils  are  called  spongioles:  these  arc  the 
growing  points,  and  the  organs  which  absorb  from  the  soil  the 
earthy  part  of  the  food  of  all  plants.  If  some  trees,  as  the 
willow  or  currant,  be  inverted  in  the  soil,  the  branches  are 
changed  to  roots,  while  the  roots  put  forth  leaves  in  the  air, 
and  the  plant  grows. 

Roots  are  of  several  different  forms,  which  have  received 
Fis-  llt  specific  names  for  the  sake 

of  convenience. 

Ramose,  or  branching 
roots,  are  those  which  send 
:off  many  ramifications  in 
various  directions,  like  the 
branches  of  a  tree:  such 
are  the  roots  of  the  oak 
and  elm.  Fig.  1 1 . 


104 


SCIENTIFIC    AGRICULTURE. 


Fig.  12.  Fusiform,  or  spindle  shaped  roots,  consist  of  a 
fleshy  stock,  tapering  downwards  to  its  extremity, 
sending  off  fibrils,  which  are  its  true  roots:  such 
are  the  raddish,  carrot  and  parsnep.  Fig.  12. 

The  napiform  root  is  a  variety  of 
the  fusiform,  in  which  the  neck  or, 
upper  part  swells  out,  so  that  its' 
diameter  equals  or  exceeds  its 
length.  The  turnip  and  turnip- 
raddish  are  examples.  Fig.  13. 

Fibrous  roots  are  made  up 
of  numerous  small  thread-like 
roots,  attached  directly  to  the 
stalk,  without  any  neck  or  main 
root :  such  are  the  roots  of  most 
grasses.  Fig.  14. 

Fasciculated  roots  differ  from 
the  fibrous  in  having  some  of  their  fibres  thickened  and  fleshy, 
as  in  the  dahlia  and  peony. 

Tuberous  roots  consist  of  fleshy,  roundish  knobs  or  tumors, 
Fis  15-  at  or  near  the  extremity  of  the  stalk,  as  in 

the  orchis :  "  the  potato  was  formerly  classed 
among  tubers, — but  as  it  uniformly  bears 
buds,  it  is  classed  among  stems."  Fig  15. 

Granulated  roots  consist  of  many  small 
rounded  bulbs  connected  together  by  fibres, 
as  in  the  common  wood  sorrel. 

Fig    16. 


Fig.  16. 


BOTANY.  105 

Besides  these  varieties  of  roots,  there  are  several  others 
which  are  peculiar,  and  distinguished  by  not  being  necessa- 
rily fixed  in  the  soil. 

Aerial  roots  are  those  which  grow  from  some  part  of  the 
plant  above  the  surface  of  the  soil  in  the  open  air.  Some 
creeping  plants,  as  the  ground  ivy,  send  forth  these  roots  from 
their  joints.  The  screw-pine  also  sends  off  roots  which  are 
several  feet  in  length  before  they  reach  the  ground.  Such 
roots  are  often  seen  in  the  common  maize. 

Floating  roots  belong  to  plants  which  float  upon  the  surface 
of  water.  The  water-starwort  is  said  to  float  upon  the  surface 
until  flowering,  when  it  sinks  and  takes  root  in  the  mud  till  its 
seeds  ripen. 

The  epiphytes,  or  plants  fixed  upon  the  branches  of  other 
species,  derive  their  nourishment  mostly  from  the  air:  such 
are  some  species  of  moss. 

Parasites  are  those  plants  which  grow  upon  other  plants ; 
and  some  of  whose  roots  are  said  to  penetrate  their  tissues 
and  subsist  upon  their  juices;  while  the  roots  of  others  are 
aerial,  and  derive  their  food  from  the  air :  such  are  the  mistle- 
toe and  dodder. 

Roots  are  divided  again  into  three  varieties,  viz:  annual, 
biennial  and  perennial,  according  to  their  duration. 

Annual  roots  are  those  which  live  only  one  year,  and  must 
be  raised  from  the  seed,  sown  every  spring, — as  beans,  peas 
and  cucumbers. 

Biennial  roote_are  those  which  live  two  years  and  do  not 
blossom  the  first  season, — but  they  produce  flowers,  fruit  and 
seeds  the  second  year,  and  then  die :  such  are  the  beet,  cab- 
bage and  carrot. 

Perennial  roots  live  several  years, — some  of  them,  as  forest 
trees,  live  to  a  very  great  age:  the  grasses,  dandelion  and 
asparagus  are  other  examples. 


106  SCIENTIFIC    AGRICULTURE. 

STRUCTURE    AND    FUNCTIONS    OF    THE    ROOT. 

The  internal  structure  of  the  root  and  stem  are  similar :  the 
fibrils  are  composed  of  vascular  tissue,  inclosed  in  a  cellular 
epidermis,  which,  however,  does  not  extend  to  the  ends  of  the 
fibrils; — these  ends  are  naked  and  spongy, — hence  they  are 
called  spongioles,  and  have  the  power  of  absorbing  large  quan- 
tities of  water. 

The  growth  of  the  root  takes  place  by  layers  upon  its 
surface  and  the  addition  of  matter  at  the  extremities.  The 
fact  is  considered  established,  [Johnston,]  that  the  spuigioles 
absorb  gaseous  as  well  as  aqueous  matters,  when  in  contact 
with  them.  The  root  absorbs  only  from  its  spongioles ;->— from 
these  it  is  carried  by  the  vessels  of  the  fibrils  to  those  of  the 
main  roots,  and  thence  into  the  stem  and  to  all  parts  of  the 
plant.  1.  Both  organic  and  inorganic  substances,  in  a  state  of 
solution  in  water,  enter  the  circulation  of  plants.  2.  The  roots 
have  the  power  of  selecting  such  substances  as  are  necessary 
for  their  food,  and  of  rejecting  those  that  are^njurious  to  their 
healthy  growth.  3.  Roots  possess  the  power  of  excreting 
certain  matters  which  are  in  excess,  or  are  unnecessary  or 
injurious  to  them.  4.  Roots  have  the  power  of  modifying  the 
fluids  as  they  pass  through  them. — [Johnston.] 

THE    STALK    OR    STEM. 

The  part  of  a  plant  which  rises  above  the  surface  of  the 
soil,  which  constitutes  the  principal  axis,  and  is  intermediate 
between  the  roots  and  branches,  is  called  the  stem.  The 
direction  of  the  stem  is  generally  vertical,  but  in  some  plants 
it  is  oblique  or  horizontal.  Stems,  like  roots,  may  be  annual, 
biennial  or  perennial.  Plants  are  divided  into  kerbs,  shrubs, 
and  trees,  according  to  the  size  and  duration  of  the  stem. 

Herbs  are  plants  with  annual  roots  and  annual  stems,  which 
do  not  become  woody:  such  are  the  grasses,  mints,  most 
flowers,  <&e. 

Shrubs  have  perennial,  woody  stems  and  roots,  divided  into 


BOTAN1T.  107 

numerous  branches  near  the  ground,  and  do  not  attain  the 
size  of  trees :  such  are  the  alder,  whortlebeny,  lilac  and  haw- 
thorn. 

Trees  have  perennial,  woody  stems  and  roots,  —  do  not 
branch  off  near  the  ground,  and  attain  a  great  size :  examples, 
elm,  oak  and  pine.  The  distinguishing  property  of  the  stem 
is  the  production  and  development  of  luds. 

Buds  are  of  two  kinds,  viz:  the  leaf -bud  and  the  flower-bud. 

The  leaf-bud  consists  of  delicate  layers  of  cellular  tissue,  or 
embryo  leaves,  covered  by  hardened  crusty  scales. 

The  "flower-bud  consists  of  the  rudiments  of  the  new  flower. 

There  are  several  subordinate  organs,  which  are  little  more 
than  appendages  to  the  stem,  and  which  it  is  unnecessary  to 
describe. 

STRUCTURE    AND    FUNCTIONS    OF    THE    STEM. 

Plants  are  divided  into  exogenous  and  endogenous. 
The  exogenous  are  those  which  grow  by  accumulation,  or 
layers  of  matter  from  the  outside.     This  class  includes  nearly 
all  forest  trees  and  most  shrubs  and  herbaceous  plants  of  tem- 
perate climates. 

The  endogenous  plants  are  those  which  grow  from  the  inside, 
or  by  accretion  of  matter  within  that  already  developed.    Most 
of  the  bulbous  plants  of  temperate  regions,  all  the  grasses,  and 
the  palms,  cane,  <fec.,  of  tropical  countries,  are  endogenous. 
The  exogenous  stem  consists  of  bark,  wood  and  pitL 
The  pith  is  a  light  spongy  substance,  at  the  centre  of  the 
stem :  it  is  composed  of  cellular  tissue,  and  seems  to  exercise 
its  peculiar  functions  only  during  the  earlier  growth  of  plants. 

[Wood. 

The  icood  is  composed  of  cylindrical  or  concentric  layers,  in- 
tersected by  medullary  rays,  which  are  those  thin  dense  plates 
of  wood  dividing  the  "grains,"  and  are  large  and  easily  seen 
in  a  piece  of  beech  or  oak  wood  which  has  been  split.  The 
pith,  together  with  the  first  layer  which  incloses  it,  are  the 


108 


SCIENTIFIC    AGRICULTURE. 


Fig.  17. 


product  of  the  first  year's  growth; 
one  new  layer  is  formed  every  suc- 
ceeding year, — so  that  the  number 
of  rings  or  "grains"  at  the  base  of 
the  stem  indicate  correctly  the  age 
of  the  tree.  Each  layer  is  composed 
of  woody  fibres,  vasiform  tissue  and 


ducts. 


Fig.  17. 


[Fig.  17.  1,  represents  an  erogenous 
stem  of  one  year's  growth;  a,  pith;  b, 
bark;  c.  medullary  rays;  d,  woody  bun- 
dles of  fibre;  2,  laticiferous  vessels  of  the 
bark.] 

The  outside,  lighter  colored  lay- 
ers constitute  the  allurmnn  or  "sap 
wood:"  the  brownish  layers  inside  are  harder  than  the  sap 
•wood,  and  are  hence  called  the  duramen. 

The  bark  forms  the  external  covering  or  integuments  of  the 
stem  and  root.  The  bark  consists  of  three  distinct  layers :  the 
outside  covering  is  called  the  epidermis, — this  layer  is  some- 
times covered  with  a  coating  of  gummy,  oily  or  resinous  matter. 
The  middle  layer  is  the  cellular  integument;  and  the  inner  coat 
the  liber.  The  two  outer  layers  are  of  cellular  structure,  "while 
the  inner  one  is  both  cellular  and  woody. 

The  sap  is  carried  by  the  vessels  through  the  alburnum  to 
the  leaves,  with  the  vessels  of  which  they  communicate:  while 
in  the  leaves,  the  sap  undergoes  some  changes,  (not  well 
understood,)  by  moans  of  the  air  and  light,  by  which  it  is 
converted  into  a  fluid  called  latex.  From  the  vessels  of  the 
under  side  of  the  leaf,  it  descends  by  the  vessels  of  the  inner 
bark ;  part  of  it  is  carried  inwards  by  the  pores  of  the  medul- 
lary rays,  and  diffused  through  the  stem,  while  the  remainder 
descends  to  the  roots,  and  is  distributed  through  them.  Sap 
is  milky,  gummy,  saccharine  bitter,  &c.,  in  various  plants. 

At  the  end  of  spring  a  portion  of  the  descending  sap,  which 


BOTANY. 


100 


is  now  transformed  into  a  viscid  glutinous  matter  called  cam- 
bium, is  deposited  between  the  liber  and  the  wood,  becomes 
organized  into  cells,  ajid  forms  a  new  layer  upon  each.  Soon 
afterwards,  the  new  layers  are  pervaded  by  woody  tubes  and 
fibres,  which  commence  at  the  leaves  and  grow  downwards. 
"  The  number  of  layers  in  the  bark  and  wood  will  always  be 
equal."  (Wood.)  The  outer  bark  of  young  twigs  seems  to 
perform  the  same  function  as  the  leaves :  in  the  cactus,  sta- 
pheliu,  and  other  plants  which  produce  no  leaves,  the  bark  must 
perform  the  same  office  as  the  leaves  do  in  plants  which  pro- 
duce them.  (Johnston.) 

^   Fig.  is. 

4 


C  C 


[Fig.  18.  3,  horizontal  section  of  an  endogenous  stem,  exhibiting  the 
bundles  of  woody  fibre,  spiral  vessels  and  ducts,  irregularly  disposed  in 
the  cellular  tissue :  5,  a,  a,  cellular  tissue ;  b,  spiral  vessels  on  inner  side 
of  dotted  ducts,  c,  c;  d,  woody  fibre  on  the  exterior  side:  4,  stem  of 
three  year's  growth;  a,  pith;  e,  bark;  b,  c,  d,  successive  annual  layers: 
6  a,  pith;  b,  spiral  vessels  of  the  medullary  sheath;  c,  dotted  ducts;  d, 
woody  fibre;  e,  bark.] 

The  endogenous  stem  exhibits  no  distinction  of  bark,  wood 
and  pith, — and  no  concentric  annual  layers  or  grains.  It  is 
composed  of  cellular  tissue,  woody  fibres,  spiral  vessels  and 

10 


110 


SCIENTIFIC    AGRICULTURE. 


ducts,  the  same  as  that  of  exogens.  The  cellular  tissue  exists 
equally  in  all  parts  of  the  plant;  the  rest  are  in  bundles,  im- 
bedded in  the  stem:  "each  bundle  consists  of  one  or  more 
ducts,  with  spiral  vessels  adjoining  their  inner  side  next  to  the 
centre  of  the  stem,  and  woody  fibres  on  the  outside,  as  in  the 
exogen. 

"  A  new  set  of  these  bundles  is  formed  annually,  or  oftener, 
proceeding  from  the  leaves,  and  passing  downwards  in  the 
central  parts  of  the  stem,  where  the  cellular  tissue  is  most 
abundant  and  soft  After  descending  awhile  in  tliis  manner, 
they  turn  outwards  and  interlace  themselves  with  those  which 
were  previously  formed." 


Oryptogamons  or  Flowerless  Planta. 


CHAPTER  III. 


STRUCTURE    AND    FUNCTIONS    OF    THE    LSAF. 

THE  leaf  is  an  extension  of  the  two  outer  layers  of  the  bark 
expanded  into  a  broad  thin  net  work:  leaves  constitute  the 
verdure  of  nearly  all  plants;  their  color  is  almost  universally 
green,  which  color  they  derive  from  a  substance  called  chloro- 
phylle,  deposited  just  beneath  the  cuticle.  Towards  the  end 
of  autumn,  after  the  verdure  of  plants  has  matured,  their  color 
is  changed  to  various  hues,  as  yellow,  orange,  red,  <fec.,  by  the 
action  of  oxygen  on  their  elements. 

Deciduous  leaves  are  those  which  fade  and  fall  off  at  the  end 
of  autumn,  annually. 

Evergreens  are  those  which  remain  green  throughout  the 
year.  .  % 

Leaves  are  arranged  in  various  ways  upon  the  stem  and 
branches  of  plants :  in  some,  as  in  the  potato,  they  are  scattered 
along  the  stem  irregularly:  in  others,  as  the  pea,  they  aie 
alternate,  or  one  above  another  on  opposite  sides  of  the  stem : 
when  two  are  against  each  other  at  the  same  joint  or  node, 
they  are  called  opposite:  when  more  than  two  are  arranged 
in  a  circle  at  the  same  node,  as  in  the  meadow  lily,  they  are 
verticillate :  in  the  pepper  and  some  others,  they  are  arranged 
spirally  around  the  stem. 

The  prolongation  of  the  leaf-stalk,  through  the  middle  of 
the  leaf,  is  called  the  midrib;  the  smaller  divisions,  or  ribs, 
which  radiate  or  go  off  from  this,  are  called  nerves. 


112 


SCIENTIFIC    AGRICULTURE. 


The  hair-like  lines  sent  off  from  the  midrib  and  nerves  are 
called  veins.  This  distinction  is  arbitrary,  as  there  is  no  dif- 
ference in  the  structure  or  function.  The  various  distributions 
of  the  veins  have  received  distinctive  names,  and  these  are  all 
included  under  the  generic  term  venation. 

FORMS  OF  LEAVES. 

Tlieforjns  of  leaves  have  also  subjected  them  to  an  arrange- 
ment under  specific  heads.  The  forms  of  leaves  are  said  by 
De  Candolle  to  depend  upon  the  length  of  the  midrib  and  the 
relative  length  of  the  veins. 

rig.  IP.  Orbicular  leaves  are  roundish,  as  in  the 

pyrola  rotundifolia,  or  round  leaf  wintergreen, 
and  nasturtion.     Fig.  19. 

Elliptical  leaves,  as  their  name     Fig.  20. 
implies,  are  elliptical  or  oval  in 
form,  as  in  the  whortleberry  and 
wintergreen.     Fig.  20. 

Lanceoate  leaves  are  long  and  tapering  at  the< 
point  like  the  blade  of  a  lancet,  as  in  the  willow  and  peach. 
Fig.  21,  a. 


BOTANY. 


113 


Pig.  22 


rig.  23. 


Cordate  leaves  are  heart-shaped,  as  in  the  lilac  and  aster 
cordifolium.  Fig.  22. 

Sagittate  leaves  have  the  form  of  an  arrow-head,  as  in  the 
sagittaria.  Fig.  23,  #. 

Reniform  leaves  are  kidney-shaped,  as  in  the  wild  ginger 
and  ground  ivy.  Fig  24. 

Linear  leaves  are  narrow,  long  and  straight,  as  in  the  grasses 
and  grains.  Fig.  21,  c. 

Deltoid  leaves  are  in  the  form  of  the  Greek  letter  delta,-  or 
nearly  triangular,  as  in  the  Lombardy  poplar.  Fig.  21,  e. 

Acerose  leaves  are  long,  narrow  and  needle-shaped,  and 
clustered  together,  as  in  the  pine.  Fig.  23,  b. 

Piimatified,  or  feather-cleft  leaves,  have  deep  clefts  between 
all  their  veins,  separating  the  leaf  into  parallel  segments,  as  in 
the  lepidium.  Fig  25,  d. 

*10 


114 


SCIENTIFIC    AGRICULTURE. 
Fig.  25.  Fig    20. 


Lyrate  leaves  have  several  deep  rounded  notches  between 
their  veins,  as  in  the  water-cress.  Fig.  25,  c. 

Connate  leaves  have  the  bases  of  opposite  leaves  united  so 
As  to  appear  like  one  entire  leaf,  as  in  the  boneset  and  sapo- 
naria*.  Fig.  26. 

Digittate  leaves  have  narrow,  deep  clefts  between  the  veins, 
with  long  segments  radiating  from  the  end  of  the  leaf-stalk,  as 
in  the  common  hemp.  Fig.  27. 

Fig    28. 

Stellate  leaves  are  arranged  around 
the  stem  in  such  a  manner  as  to  form  a 
star,  as  in  the  red  lily.  Fig.  28. 

Loled  leaves  are  deeply  indented  or 
cleft  at  their  margins,  so  as  to  divide 
them  into  lobes,  as  in  the  liverwort.  Fig. 
.29,  a. 


BOTANY. 


115 


Sinuate  leaves  have  their  margins  divided  by  deep  roundish 
clefts,  as  in  the  white  oak.     Fig.  29,  b. 

Fig    29. 


Emarginate  leaves  are  irregular,  having  but  slight  indenta- 
tions in  the  margin.  Fig.  29,  c. 

Tubulate  leaves  have  the  sides  or  margins  united  so  as  to 
form  a  cup,  as  in  the  side-saddle  and  pitcher  plant.  Fig.  30. 

Fig    30. 


Fig   31. 


Compound  leaves  consist  of 
several  small  leaves  on  separate 
leaf-stalks,  and  arranged  along 
the  opposite  sides  of  the  same 
stem,  as  in  the  hedysarum.  Fig.  31 . 

Ternate    leaves       rig.  32. 
arise  in  threes  from 
the  same  leaf- stalk. 
Fig.  32. 

Alternate  is  a  se- 
cond division  by 
threes. 


116 


SCIENTIFIC  AGRICULTURE. 


Fig.  33.  Leaves  are  opposite  when  placed  at  equal 

distances  in  pairs  on  opposite  sides  of  the  stem. 
Fig.  33. 

These  are  the  principal  forms  of  leaves; 
still,  many  other  names  are  given  by  botanists 
to  the  various  modifications  of  these.  Specific 
terms  are  employed  also  in  describing  the 
stem,  margin,  base,  point  and  surfaces  of  leaves. 
There  are  also  various  appendages  to  the 
leaves,  which  have  distinctive  names,-  in  sys- 
tematic works  on  botany.  To  describe  all  the 
minor  points  in  the  organography  of  plants 
would  exceed  our  limits, — and,  besides,  it  would  render  this 
brief  outline  of  botany  too  complex  to  be  interesting  to  the 
general  reader. 

MINUTE  STRUCTURE  OF  THE  LEAF. 

The  frame  work  of  the  leaf  is  an  extension  and  expansion  of 
the  medullary  sheath,  which  is  composed  of  woody  fibre  and 
vessels.  The  integument,  or  outer  covering  of  the  leaf,  is 
the  same  as  that  of  the  bark,  of  which  it  is  a  continuation. 

The  cellular  tissue  peculiar  to  the  leaf  is  called  its  paren- 
chyma. This  parenchyma  exists  in  two  layers  of  cells,  which 
differ  somewhat  in  structure.  Within  the  cells,  and  adhering 
to  their  walls,  are  the  minute  green  particles  of  cklorophylle, 
F*g  34.  which  give  color  to  the  leaf:  the  empty 

•spaces  between  the  cells  communicate 
with  the  external  air  by  means  of  sto~ 
mata,  or  mouths,  which,  in  most  plants, 
are  found  only  on  the  lower  surface. 
In  all  those  plants  whose  leaves  are 
vertical,  as  the  iris,  they  are  on  both 

[Fig.  34.  Magnified  sides  equally:  in  the  water  lily,  they 
section  of  the  epidermis  .  ,  .  .,  /.  *  ,-, 

•of  the  my>  showing  tte  exist   only  in   the    upper   surface,  the 


storoata,  c,  >c. 


lower  surface  being  in  contact  with  the 


BOTANY. 


117 


Tlio  veins  which  carry  the  latex,  or  nutricious  fluid  of 
the  leaf,  "having  reached  the  edge  of  the  leaf,  double  back 
upon  themselves,"  spread  through  the  lower  surface,  and  are 
again  collected,  and  returned  through  the  leaf-stalk  into  the 
bark. 

Fig.  35. 


[Fig.  35  shows  a  magnified  section  of  the  leaf  of  the  lily:  the  upper 
surface,  a,  consists  of  flattened  cells  of  the  epidermis,  arranged  in  a 
single  layer;  beneath  this,  b,  is  the  more  compact  part  of  the  paren- 
chyma, consisting  of  a  layer  of  oblong  cells  placed  in  such  a  position 
that  their  longer  axis  is  perpendicular  to  the  leaf's  surface.  Next 
below  is  the  parenchyma  of  the  lower  surface,  c,  composed  of  oblong 
cells  arranged  longitudinally,  and  so  loosely  compacted  as  to  leave 
larger  spaces  between.  Lastly,  d,  is  the  epidermis  of  the  lower  sur- 
face, with  stomata,  e,  e,  opening  into  air  chambers,  f.] 

FUNCTIONS    OF    THE    LEAF. 

The  functions  of  the  leaf  are,  exhalation,  absorption,  respi- 
ration and  digestion.  The  ultimate  end  of  these  functions  is 
to  produce  the  necessary  changes  on  the  crude  sap  brought 
up  from  the  roots,  and  to  convert  it  into  the  latex,  which  is  the 
proper  nutrition  of  the  growing  plant :  this  ftuid  is  to  the  plant 
what  the  arterial  blood  is  to  the  animal  system. 

Exhalation  in  plants  is  the  throwing  off  of  the  excess  of 
water  in  the  sap,  so  as  to  leave  it  in  a  more  concentrated  form, 
and  consequently  better  adapted  to  nutrition :  exhalation  takes 
place  through  the  stomata,  and  is  different  from  mere  evapo- 
ration, which  depends  upon  the  state  of  temperature  and  air. 
Exhalation  is  supposed  to  cease  during  darkness. 

Absorption  is  performed  mainly  by  the  roots,  in  nearly  all 
plants :  when,  however,  these  are  defective  or  wanting,  the  leaf 


118  SCIENTIFIC    AGRICULTURE. 

assumes  the  vicarious  office  of  absorption.  The  invigorating 
effect  of  a  shower  of  rain  oil  the  leaves  of  parched  and  wilted 
plants,  is  seen  long  before  the  water  could  have  reached  the 
roots  and  have  been  carried  up  to  the  leaves :  this  effect  must 
be  produced,  therefore,  by  the  absorption  of  moisture  by  the 
leaf.  This  action  takes  place  mostly  from  the  lower  surface  of 
the  leaf. 

Respiration  in  plants  consists,  as  in  animals,  in  the  absorp- 
tion of  oxygen  from  the  air,  and  the  giving  off  of  carbonic 
acid.  It  is  performed  mainly  by  the  leaves,  but  is  performed 
to  some  extent  by  other  parts  also :  it  continues  without  inter- 
mission by  day  as  well  as  by  night,  during  the  life  of  the  plant 
Respiration  is  most  active  during  the  processes  of  germination 
and  flowering:  a  constant  supply  of  oxygen,  and  the  daily 
presence  of  light,  are  indispensable  to  the  growth  and  vitality 
of  the  plant 

Digestion  comprises  all  those  changes  which  the  mineral, 
aqueous  and  gaseous  matters  undergo  after  entering  the  plant, 
until  they  are  assimilated  and  become  a  part  of  the  organism. 
"  It  consists  in  the  decomposition  of  carbonic  acid  by  the  green 
tissues  of  the  leaves,  under  the  stimulus  of  the  light,  the  fixa- 
tion of  the  solid  carbon,  and  the  evolution  of  pure  oxygen." 

[Wood. 

INFLORESCENCE. 

Inflorescence  is  the  term  used  to  indicate  the  peculiar 
arrangement  of  flowers  upon  the  stem  and  branches  of  plants ; 
also  their  successive  development  in  different  parts  of  the  same 
plant  Flowers  are  said  to  be  terminal  and  axillary,  in  regard 
to  their  position  on  the  stem. 

Terminal  flowers  are  placed  at  the  end  or  summit  of  the 
branch  or  flower  stalk. 

Axillary  flowers  are  placed  in  the  angle  formed  by  the 
branch  or  leaf-stalk,  and  the  primary  central  stem,  or  larger 
lateral  braaches. 


BOTANY.  119 

The  peduncle  is  the  flower-stalk,  or  that  part  of  the  stem 
which  is  attached  to  and  supports  the  flowers :  it  may  be  simple 
or  branching,  and  it  may  be  entirely  absent, 
rig  36 


[Fig.  36  shows  a  papilionaceous  flower  with  its  peduncles-3 

A  scape  is  a  flower-stalk,  or  peduncle,  which  springs  imme- 
diately from  the  root,  in  those  plants  which  are  called  stemless, 
as  the  sarracenia,  hyacynthus,  &c. 

A  rachis  is  the  main  axis,  or  stem,  of  a  compound  peduncle, 
along  which  are  arranged  the  flowers,  as  in  the  currant,  grape, 
grasses,  plantain,  &c. 

A  flower  is  said  to  be  solitary,  when  a  single  terminal  or 
axillary  flower  is  developed,  as  in  the  erythronium  and  con- 
volvulus. The  successive  evolution  of  flowers  is  distinguished 
into  two  varieties,  viz :  the  centripetal  and  centrifugal. 

In  centripetal  inflorescence,  the  blooming  of  the  flower  com- 
mences at  the  circumference  and  proceeds  towards  the  centre, 
as  in  the  mustard,  carrot,  &c. 

In  centrifugal  inflorescence,  the  blossoming  commences  at 
the  terminal  or  central  flower,  and  advances  laterally  to  the 
circumference,  as  in  the  elder,  pink  and  sweet-william.  These 
two  modes  of  inflorescence  are  sometimes  combined  in  the 
same  plant. — [Gray.] 

There  are  several  varieties  of  centripetal  inflorescence,  which 


120 


SCIENTIFIC    AGRICUJLTURE. 


arc  designated  by  specific  terms ;  as  the  spike,  raceme,  amcnt, 
spadix,  corymb,  umbel,  head,  panicle  and  thyrse. 

Of  centrifugal  inflorescence,  there  are  also  several  varieties, 
as  the  cyme,  fascicle,  whorl,  or  verticil,  &c. 

Fig    37. 


[Fig.  37  represents  a  head  of  oats  showing  an  example  of  a  panicled 
flower.] 

Tendrils, 


CHAPTER"  IV. 


GENERAL   REMARKS. 

THE  dissemination  of  seeds  is  a  subject  not  unworthy  o* 
allusion.  It  is  known  to  botanists,  that  nearly  all  plants  have 
particular  localities  to  which  they  are  indigenous.  But,  by 
various  means,  they  have  become  more  or  less  distributed  over 
different  and  distant  parts  of  the  earth.  Some  seeds,  as  those 
of  the  thistle  and  dandelion,  are  furnished  with  a  little  plume 
or  wing,  by  means  of  which  they  are  wafted  by  winds  to  great 
distances,  and  thus  sown  in  a  soil  and  locality  where  the 
species  was  never  before  known.  Some  seeds  are  furnished 
with  hooks  or  burs,  by  means  of  which  they  attach  themselves 
to  the  clothing  of  men  and  animals :  seeds  are  also  eaten  by 
animals  and  birds,  carried  to  great  distances,  voided  undigested 
and  without  injury  to  their  vitality,  germinate  wherever  they 
are  deposited. 

Many  seeds  are  so  protected  by  a  thick  dense  pericarp,  that 
they  make  long  voyages,  being  carried  along  by  the  current 
of  streams,  or  the  ebbing  and  flowing  of  tides,  until  they  reach 
a  distant  country,  and  perhaps  even  another  continent,  and 
there  propagate  and  establish  their  species.  They  are  carried 
also  by  ships  and  other  conveyances  engaged  in  commercial 
transportations,  as  well  by  accident  as  by  design  for  the 
purpose  of  cultivation.  Many  seeds  retain  their  vitality  after 
boiling,  digestion  in  alcohol,  and  being  buried  in  the  earth  for 

11 


122  SCIENTIFIC    AGRICULTURE. 

centuries.  Dr.  Lindley  mentions  a  remarkable  instance  of  the 
longevity  of  raspberry  seeds,  which,  as  proven  by  circum- 
stances, must  have  been  1,600  years  old,  and  were  found 
thirty  feet  below  the  surface  of  the  earth.  Oily  seeds  are 
more  liable  to  putrify  and  lose  their  vitality  than  others. 

The  blooming  of  flowers  was  thought,  during  the  dark  and 
middle  ages,  when  the  human  mind  was  blinded  by  the 
grossest  superstition,  to  be  emblematical  of  something  con- 
nected with  religion:  thus  when  the  time  of  the  blossoming 
of  a  flower  fell  on  the  birthday  of  a  saint,  or  on  the  day  of  a 
martyrdom,  that  flower  was  consecrated  or  dedicated  to  such 
saint  or  martyr. 

Plants  exhibit  many  phenomena  which  seem  to  be  connec- 
ted with  atmospheric  conditions  and  changes :  thus  it  is  said 
a  storm  may  be  predicted  by  the  folding  or  opening  of  certain 
flowers ;  also  that  a  clear  sky,  thunder,  wind,  &c,  may  be  fore- 
told by  the  various  other  phenomena  observed  to  take  place 
in  the  different  organs  of  plants.  Some  plants  are  capable  of 
enduring  a  high  degree  of  heat:  those  of  the  tropics  sustain 
a  temperature  which  would  be  intolerable  to  animals  for  a 
great  length  of  time :  others  are  found  immersed  in  the  waters 
of  boiling  springs,  and  in  a  state  of  thrifty  vegetation. 

Every  country  exhibits  a  flora,  or  botanical  character,  pecu- 
liar to  itself.  The  influence  of  light  and  heat  on  the  growth 
of  plants  is  seen  to  be  powerful  and  important.  In  the  polar 
regions,  where  almost  perpetual  winter  reigns,  the  vegetation 
is  rigid,  scanty  and  stinted :  the  centre  of  the  frigid  zone,  in 
fact,  is  totally  destitute  of  vegetable  life.  After  passing  the 
arctic  circle,  we  find  a  few  species  of  mosses,  lichens  and  ferns, 
and  a  few  shrubs.  The  only  country  in  this  zone  where  the 
grains  can  be  successfully  cultivated,  is  Lapland.  The  tem- 
perate zone  produces  most  species  of  useful  nutrient  plants, 
such  as  the  grains,  berries,  fruits  and  grasses,  as  well  as  valu- 
able timber  trees.  The  torrid  zone  produces  every  variety  of 


BOTANY.  123 

vegetation  from  the  equator  to  the  poles:  this  variety  depends 
upon  the  altitude  at  which  they  are  found;  the  low  land  pro- 
duces the  most  luscious  fruits  and  stately  trees,  with  a  vast 
variety  of  flowers  and  spices. 

As  vegetation  ascends  the  mountain  heights,  even  under 
the  equator,  it  assimilates,  according  as  the  climate  becomes 
less  congenial,  to  that  of  the  colder  regions,  in  the  same  way 
as  when  receding  from  the  equator  towards  the  poles.  Plants, 
like  animals,  are  liable  to  various  diseases :  no  inorganic  body 
can  be  said  to  suffer  from  disease, — although  they  are  subject 
to  decomposition  and  disintegration,  they  are  not  capable  of 
diseased  action,  because  destitute  of  vitality,  which  i^  indispen- 
sable to  such  a  process.  Plants  may  become  diseased  from 
a  deficiency  or  excess  of  food,  air,  light,  water,  heat, — or  from 
cold,  noxious  vapors,  external  injuries,  insects,  parasites  and 
hereditary  organic  or  functional  debility.  They  are  also 
liable  to  diseases  peculiar  to  old  age  and  excessive  action,  in 
the  same  manner  as  animals.  Thus  they  suffer  from  anemia,* 
or  want  of  fluids,  like  aged  persons:  they  sometimes  labor 
under  dropsy,  from  deficiency  of  light, — and  from  other  causes 
they  suffer  and  die  from  dry  mortification* 

Lastly,  plants  are  liable  to  disease  and  death  from  poisoning 
and  contagion.  The  economical  uses  of  plants  are  well  known, 
and  require  only  a  passing  notice :  forest  trees,  and  some  parts 
of  other  plants,  are  indispensable  in  the  arts:  cereals,  fruits 
and  roots,  are  used  as  food  for  both  man  and  beast :  the  grasses, 
lichens,  mosses  and  herbs  serve  as  food  for  animals:  various 
plants,  and  the  substances  derived  from  them,  are  also  used  as 
medicines.  Plants  designed  for  medicinal  purposes  should  be 
collected  at  a  time  when  the  whole  vitality  and  forces  are  not 
engaged  in  the  growth  of  the  plant  and  maturity  of  the  flower 
and  seed :  herbs  should  be  gathered  soon  after  flowering,  or 
when  the  seed  is  nearly  ripened :  roots,  if  annual,  should  be 

*  Terms  proposed  by  the  author. 


124  SCIENTIFIC    AGRICULTURE. 

gathered  after  the  stem  and  foliage  are  withered  in  autumn, 
or  before  the  old  root  begins  to  decay  in  the  spring:  barks 
possess  more  strength  if  taken  after  the  descent  of  the  sap  has 
ceased,  and  the  cambium  has  become  hardened  into  wood  and 
bark. 

Some  remarks  on  the  collection  and  preparation  of  plants 
for  herbariums,  and  upon  botanical  analysis,  classification  and 
nomenclature,  might  be  made;  but  they  would  be  of  little 
service,  as  they  would  anticipate  a  step  in  the  science  which 
lies  beyond  the  limits  of  this  treatise. 

* 


PART    IV. 

METEOROLOGY. 

CHAPTER  I. 

METEOROLOGY  is  the  science  which  treats  of  all  the  various 
phenomena  which  take  place  in  the  atmosphere.  "  Under  the 
term  meteorology,  it  is  now  usual  to  include,  not  merely  the 
accidental  phenomena  to  which  the  name  of  meteor  is  applied, 
but  every  terrestrial  as  well  as  atmospherical  phenomenon, 
whether  accidental  or  permanent,  depending  on  the  action  of 
heat,  light,  electricity,  and  magnetism.  In  this  extended 
signification,  meteorology  comprehends  climatology  and  the 
greater  part  of  physical  geography ;  and  its  object  is  to  deter- 
mine the  diversified  and  incessantly  changing  influences  of  the 
four  great  agents  of  nature  now  named,  on  land,  in  the  sea, 
and  in  the  atmosphere." — [Brande.] 

A  meteor  is  any  phenomenon  of  a  transitory  nature,  which 
appears  in  the  atmosphere.  The  various  conditions  and  changes 
which  take  place  in  the  air  incessantly,  with  respect  to  heat, 
cold,  moisture,  dryness,  &c.,  are  called  weather.  Observations 
have  been  made  in  all  ages  of  the  world  upon  these  phenomena, 
in  order  to  explain  their  causes  and  foretell  the  changes  of 
weather.  But  there  are  so  many  conditions  to  be  considered, 
and  so  many  influences  which  probably  can  never  be  under- 


126  SCIENTIFIC    AGRICULTURE. 

4 

stood,  that  there  is  little  certainty  in  all  the  theories  and 
weather  tables  which  have  been  formed.  Although  many  of 
the  meteorological  phenomena  are  somewhat  well  understood 
in  their  individual  nature,  still,  when  they  are  combined,  their 
operation  is  exceedingly  complex,  and  the  number  of  their 
changes  almost  infinite. 

Records  of  past  changes  of  weather  have  long  been  kept, 
but  it  has  been  found  by  observation  and  comparison  of  the 
results  of  different  seasons  and  years,  that  few  data  are 
obtained,  on  which  to  ground  any  prognostications  of  the 
future.  Some  individuals  have,  by  long  and  close  observation, 
attained  some  apparent  accuracy  of  judgment  in  relation  to  the 
phases  of  the  weather;  but  their  conclusions  were  not  of  a 
nature  to  be  systemized  and  transmitted  to  posterity ;  so  that, 
if  any  real  attainment  has  been  made  in  this  way,  it  has 
always  been  lost  with  the  observer. 

"The  registers  which  are  kept  in  different  observatories, 
prove,  contrary  to  popular  belief  that  the  changes  of  weather 
are  in  no  way  whatever  dependent  on  the  phases  of  the  moon." 
Although  the  ever  varying  and  endless  changes  of  weather 
are  all  the  necessary  results  of  fixed  laws,  yet  it  is  doubtful 
whether  these  laws  will  ever  be  sufficiently  understood  to 
enable  us  to  reduce  our  knowledge  respecting  them  to  demon- 
strative ccertainty. 

CLIMATE. 

Climate,  in  its  most  extended  signification,  embraces  all  the 
modifications  of  atmospheric  temperature  and  conditions,  and 
the  principal  causes  on  which  they  are  dependent:  besides 
temperature,  it  includes  humidity,  dryness,  winds,  barometrical 
conditions,  purity  of  air,  &c.  The  principal  causes  which  tend 
to  modify  climate  are,  latitude,  altitude,  direction  in  which  the 
sun' sprays  fall  upon  the  earth,  configuration  and  aspect  of  the 
land,  its  proximity  and  relation  to  the  sea,  direction  of  the 
wind,  density  of  the  atmosphere,  number  of  rays  of  the  sun 


METEOROLOGY.  127 

which  are  absorbed,  amount  of  vegetation,  character  of  the 
soil,  and  state  of  agriculture. 

But  among  all  these  causes  none  have  so  important  an 
influence  on  determining  the  climate  of  a  country  as  latitude 
and  altitude.  The  degrees  of  heat  are  not  always  equal  for 
the  same  latitude;  thus  at  Rome,  in  latitude  63°  north,  the 
mean  temperature  is  the  same  as  that  of  Raleigh,  North 
Carolina,  in  latitude  36°  north. 

Lines  passing  through  points  on  the  surface  of  the  earth  at 
which  the  mean  annual  temperature  is  the  same,  are  called 
isothermal  lines.  These  lines  do  not  pass  round  the  earth  in 
a  direct  course  like  the  parallels  of  latitude,  but  they  vary  so 
as  to  assume  a  tortuous  direction. 

The  isochimenal  lines,  or  lines  of  equal  cold,  or  equal 
winter,  vary  much  more  than  the  lines  of  equal  summer. 
The  reason  why  latitude  affects  the  temperature  of  a  climate, 
is  because  it  varies  the  obliquity  of  the  sun's  rays  in  relation  to 
the  earth.  This,  however,  is  not  the  cause  of  the  difference  in 
the  length  of  day  and  night  at  different  places. 

The  following  table  from  Muller  shows  the  length  of  the 
longest  day  for  the  different  latitudes. 

Polar  Elevation.  Length  of  longest  day. 

0°  12  hours. 

16°44/  13 

30°48'  14 

49°22'  16 

63°23'  20       " 

66°32'  24       " 

67°23'  1  month. 

73°39'  3       « 

90°  6       " 

Altitude  has  an  important  effect  on  determining  the  mean 
temperature  on  all  places,  whatever  may  be  their  latitude. 
The  temperature  diminishes  from  the  surface  upwards  as  far 


128  SCIENTIFIC    AGRICULTURE. 

as  man  has  ever  ascended,  and  probably  beyond  this  point  to 
the  very  limit  of  the  atmosphere.  The  interior  of  the  earth  is 
supposed  to  be  yet  in  a  fluid  state  from  the  effects  of  heat ; 
the  solid  outside  crust  constituting  only  y^  part  of  its  whole 
diameter:  at  50  to  40  feet  below  the  surface,  invariable  tem- 
perature prevails;  that  is,  there  is  always  an  equilibrium,  so 
that  the  mercury  in  a  thermometer  would  remain  stationary 
at  this  depth,  whatever  might  be  the  temperature  above  in 
the  open  air.  This  point  would  be  at  the  surface  if  the  tem- 
perature of  the  air  was  always  the  same.  The  increase  of 
cold  upwards  from  the  earth  is  at  the  rate  of  1°  F.  for  every 
100  yards.  The  snow  line,  or  line  of  perpetual  congelation, 
varies  less  in  proportion  to  latitude  than  altitude :  thus  it  will 
be  seen  by  the  table  below,  that  this  line  is  much  lower  at  the 
equator  than  in  higher  latitudes  in  proportion. 

Table  of  Snow  Lines  from  Mutter. 

Coast  of  Norway,      2,340  feet  above  sea  level. 

Iceland,  3,042  "  «  "  « 

Alps,  8,801  "  "  "  " 

MtEtna,  9,441  «  «  «  « 

Himmalayas,  14,625  "  x«  «  « 

Mexico,  14,625  "  "  "  " 

Quito,  15,600  "  "  "  " 

There  are  three  reasons  given  by  Dr.  Brande,  why  the  cold 
increases  as  we  ascend,  viz:  1.  The  absorption  of  the  sun's 
rays  in  the  denser  strata  of  the  atmosphere  near  the  surface 
of  the  earth.  2.  Radiation  of  caloric  from  the  earth.  3.  The 
ascending  current  of  air. 

Configuration  of  the  land  varies  the  climate  of  a  country : 
a  plain  is  hotter  than  an  uneven  surface,  all  other  conditions 
being  equal.  The  sand  on  the  desert  plains  of  Africa  some- 
times attains  a  temperature  of  122°  F.  The  side  of  a  moun- 
tain or  hill,  which  faces  the  sun,  is  warmer  than  the  opposite 


METEOROLOGY.  129 

side,  for  the  plain  reason  that  its  rays  strike  upon  it  more 
vertically. 

Proximity  or  distance  from  the  ocean  is  another  cause 
which  varies  climate.  Small  islands  and  peninsulas  have 
milder  winters  and  fresher  summers  than  the  interior  of  conti- 
nents in  the  same  latitude. 

The  refrigerating  effect  of  winds  blowing  from  the  polar 
seas  is  felt  in  countries  at  great  distances :  the  reverberation  of 
winds  among  mountains  also  increases  the  cold  and  heat  of 
certain  localities.  The  other  causes  upon  which  climate  is 
dependent,  are  considered  in  another  place.  The  -  following 
table  from  Muller,  shows  the  mean  temperature  of  several 
different  places. 


130 


SCIENTIFIC    AGRICULTURE. 


Table  showing  the  mean  temperature  of  several  places  during 
several  years, — part  of  one  from  Mutter's  Phys.  and  Me'ty. 


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132  SCIENTIFIC    AGRICULTURE. 

EXPLANATION    OF    THE    CUT. 

This  cut  is  designed  to  show  the  latitude  and  altitude  at 
which  some  of  the  most  important  plants  flourish  in  the 
greatest  perfection.  It  shows  also  the  latitude  in  which  various 
winds  prevail, — the  latitude  where  there  is  little  or  no  rain 
and  also  where  there  is  almost  constant  rain.  The  scale  of 
miles  on  the  left  hand  of  the  cut  shows  the  height  of  the 
mountains,  the  elevation  at  which  plants  grow  on  their  sides, 
and  the  line  of  perpetual  snow.  On  the  right  hand  are  the 
degrees  of  latitude.  The  locality  of  plants,  as  shown  by  the 
table,  nrj  not  perhaps  strictly  accurate  in  all  cases;  but  they 
approximate  correctness  sufficiently  near  for  all  ordinary  calcu- 
lations. 


METEOROLOGY.  133 

INFLUENCE  OF  AGRICULTURE  ON  THE  CLIMATE  AND  THE  ANNUAL 
FALL    OF   RAIN, 

The  question,  wlietlier  the  clearing  away  of  forests  and  the 
labors  of  the  agriculturalist  have  had  any  influence  in  lessening 
the  annual  quantity  of  rain  and  the  quantity  of  water  in  streams, 
as  well  as  in  modifying  the  climate,  is  one  of  considerable 
interest  and  importance.  The  clearing  away  of  forests,  so  as 
to  allow^of  free  evaporation  of  water  from  marshes,  and  per- 
mit the  access  of  the  sun's  rays  to  the  soil,  most  certainly  has 
a  tendency  to  equalize  the  distribution  of  heat,  if  it  does  not 
actually  raise  the  mean  annual  temperature.  The  mean  tem- 
perature of  the  whole  earth,  however,  was  much  higher 
formerly  than  at  present.  The  tillage  of  the  soil,  by  rendering- 
it  loose,  and  exposing  a  greater  surface  to  the  action  of  heat 
and  air,  favors  evaporation,  and  in  this  way  makes  a  cold,  wet 
soil,  dry  and  warm.  It  also  increases  the  capacity  of  the  soil 
for  heat,  and  favors  nocturnal  radiation  and  the  formation  of 
dew :  but  perhaps  this  fact  goes  about  as  far  to  sustain  one 
side  of  the  question  as  the  other. 

It  is  a  fact  universally  admitted  by  geologists,  that  the  level 
of  the  waters  of  the  earth  have  every  where  undergone  a 
change.  The  instances  are  numerous,  in  which  rivers,  lakes, 
seas  and  marshes,  have  been  greatly  diminished  or  totally 
dried  up;  this  may  be  one  of  those  phenomena  which  is 
evident  to  all,  but  which  is  nevertheless  difficult  clearly  to 
explain.  Islands  have  risen  out  of  the  sea,  coasts  have  been 
left  dry  by  the  receding  of  the  waters,  and  the  beds  of  large 
rivers  have  become  dry  arable  soil.  This  has  of  course  been 
in  some  instances  owing  to  the  actual  elevation  of  portions  of 
land  by  some  subterranean  force:  and  it  is  also  true  that 
portions  have  been  submerged  by  similar  causes.  But  these 
causes  are  insufficient  to  account  for  the  general  drying  of 
streams  and  diminution  of  rains  in  cleared  agricultural  dis- 
tricts. "  In  felling  the  trees  which  covered  the  crowns  and 
slopes  of  mountains,  men  in  all  climates  seem  to  be  bringing 

12 


134  SCIENTIFIC   AGRICULTURE. 

upon  future  generations  two  calamities  at  once, — a  want  of 
fuel  and  a  scarcity  of  water."— [Humboldt.] 

The  rainy  season  is  less  regular  in  countries  where  the  soil 
is  dry  and  naked,  than  where  it  is  moist  and  covered  with 
dense  forests  or  luxuriant  vegetation.  In  some  parts  of  South 
America,  which  are  clothed  with  ancient  and  large  forests,  rain 
is  falling  almost  incessantly :  but  in  the  same  country,  where 
there  are  wide  extended  plains  and  little  vegetation,  it  seldom 
or  never  rains.  Boussingault  states,  that  when  he  was  in 
Payta,  in  South  America,  the  inhabitants  informed  him  it  had 
not  rained  there  in  seventeen  years.  The  conclusions  to  which 
he  arrived  on  this  subject,  part  of  them  sustained  also  by 
Humboldt  and  Dr.  Hitchcock,  are  as  follows. 

1.  "That  extensive  destruction  of  forests  lessens  the  quan- 
tity of  running  water  in  a  country. 

2.  "  That  it  is  impossible  to  say  precisely  whether  this  dimi- 
nution is  due  to  a  less  mean  annual  quantity  of  rain,  or  to 
more  active  evaporation,  or  to  these  two  effects  combined. 

3.  "  That  the  quantity  of  running  water  does  not  appear  to 
have  suffered  any  diminution  or  change  in  countries  which 
have  known  nothing  of  agricultural  improvement. 

4.  "That  independent  of  preserving  running  streams,  by 
opposing  an  obstacle  to  evaporation,  forests  economize  and 
regulate  their  flow. 

5.  "That   agriculture    established   in  a  dry  country,  not 
covered  with  forests,  dissipates  an  additional  portion  of  its 
running  water. 

6.  "That  clearings  of  forest  land  of  limited  extent  may 
cause  the  disappearance   of  particular  springs,  -without  our 
being  therefore  authorised  to  conclude  that  the  mean  annual 
quantity  of  rain  has  been  diminished. 

7.  "  That  in  assuming  the  meteorological  data  collected  in 
intertropical  countries,  it  may  be  presumed  that  clearing  off 
the  forests  does  actually  dimmish  the  mean  annual  quantity 
of  rain  which  falls." 


CHAJPTER  IL 


THE  philosophical  principles  upon  which  the  phenomena  of 
rain  are  immediately  dependent,  are  not  yet  well  settled :  rain. 
is  supposed,  however,  by  many  of  the  best  writers,  to  depend 
upon  the  action  of  electricity  for  its  origin.  All  causes  which 
have  a  tendency  to  reduce  the  temperature  of  the  air,  cause  a 
precipitation  of  moisture.  When  the  aqueous  vapor  which  is 
held  in  suspension  by  the  air  becomes  condensed  by  cold,  the 
minute  vesicles  coalesce  and  form  drops,  which  by  their  gravity 
descend  through  the  air,  which  is  no  longer  capable  of  sus- 
taining them. 

The  drops  of  rain  are  said  to  be  from  one  twenty  fifth  to 
one  third  of  an  inch  in  diameter :  when  they  descend  through 
a  stratum  of  dry  air,  they  are  partly  dissipated  by  evaporation. 
This  accounts  in  part  for  the  fact  that  there  is  less  rain  on 
plains  than  on  mountains. 

The  same  latitudes  have  not  the  same  quantity  of  rain! 
this,  like  climate,  is  modified  by  various  local  circumstances, — 
as  altitude,  proximity  to  the  sea,  direction  and  prevalence  of 
winds,  agricultural  condition,  forests,  &c.  The  quantity  of 
rain  which  falls  during  the  year  is  greatest  at  the  equator,  and 
diminishes  as  we  leave  this  point  and  approach  the  poles. 

The  quantity  also  which  falls  during  the  night  and  during 
the  day,  varies  at  different  places :  in  Europe  more  rain  falls 
during  the  day  than  during  the  night  time;  while  in  South 


136  SCIENTIFIC    AGRICULTURE. 

America  more  falls  during  night  thaji  during  day.  The  mean 
quantity  of  rain  is  less  as  we  ascend  above  the  sea  level :  it  is 
more  in  the  same  latitudes  where  the  mean  temperature  is 
68°  F.,  than  at  any  point  above  or  below  this. 

Rains  become  less  periodical  and  regular  as  we  leave  the 
equator.  The  mean  annual  quantity  of  rain  in  Europe,  between 
latitudes  35°  and  50°  north,  (and  probably  the  same  would  be 
nearly  true  of  similar  latitudes  in  the  United  States,)  is  from 
25  to  45  inches. 

The  mean  quantity,  as  shown  by  the  report  of  the  Regents 
of  the  University  of  New  York  to  the  Legislature,  for  the  last 
ten  or  fifteen  years,  as  measured  at  thirty  different  places  in 
this  state,  is  35.84  inches.  Of  these  various  estimates,  43.65 
was  the  greatest  number  of  inches, — which  fell  at  "  Erasmus 
Hall,"  Long  Island:  the  smallest  number  was  28.14,  which 
fell  in  St.  Lawrence  county.  We  see  from  tables  in  Bous- 
singault's  work,  that  most  falls  in  autumn  and  least  in  spring: 
we  see  also  that  most  falls  in  July  and  least  in  March  of  any 
months  in  the  year. 

This  table  is  from  the  record  kept  ly  L.  Wetherell,  Esq.,  at 
the  Rochester  Collegiate  Institute. 
Greatest  annual  mean  temperature  for  13  years,  ending 

with  1847,  39°99 

Least  do.  -       25  46 

Greatest  mean  temperature  of  one  year,    -     -     48  60 
Least         "  "  "          -    -       43  71 

Highest  heat,  July,  1845,    -  -     102 

Lowest     "      Feb.,  1836,  8°  below  zero. 
Most  rain  in  one  month,  Oct.,  1846,  6.79  inches. 

Least  "     "     "         «       Jan.,  1837,  0.16 

DEW    AND    FROST. 

All  bodies  in  nature  are  constantly  undergoing  a  change  of 
temperature :  however  hot  or  cold  a  body  may  be,  it  is  eon- 


METEOROLOGY. 

tinually  giving  out  heat,^ither  by  radiation  or  by  contact,  or 
it  is  receiving  and  absorbing  heat  from  other  bodies.  Upon 
the  principle  that  heat  tends  to  seek  an  equilibrium,  by  means 
of  radiation  and  absorption  among  bodies,  the  production  of 
dew  and  frost  may  be  accounted  for. 

During  the  absence  of  the  sun,  a  great  quantity  of  heat  is 
dissipated  from  the  surface  of  the  earth  by  ladiation:  by  this 
means,  when  the  night  is  clear,  the  temperature  is  considerably 
lowered :  when,  however,  the  earth  is  overhung  by  a  canopy 
of  clouds,  they  radiate  in  return,  or  reflect,  and  thus  maintain 
an  almost  uniform  temperature.  When  the  clouds  are  absent, 
all  the  heat  radiated  by  the  earth  is  lost  in  the  upper  regions 
of  space,  and  the  surface  is  reduced  in  temperature  many 
degrees  below  the  atmosphere. 

"  The  stratum  of  air  which  lies  in  contact  with  the  surface 
of  the  ground  is  then  cooled  by  contact,  and  a  portion  of  the 
watery  vapor  which  it  had  possessed  in  the  elastic  form,  is 
deposited  as  liquid  water.  If  the  temperature  of  the  air  be 
itself  low,  and  the  night  very  clear,  the  cooling  may  proceed 
so  far  that  the  drops  of  dew  at  the  moment  of  their  deposition 
shall  be  frozen,  and  thus  form  frost." — [Kane.]  The  fact  is 
familiar  to  most  observers,  that  dew  and  frost  are  formed  only 
in  clear  starlight  and  still  nights,  —  and  then  only  on  the 
surface  of  good  radiators. 

The  cooling  of  the  earth's  surface  by  the  loss  of  radiant 
heat,  is  prevented  by  a  covering  of  snow  or  any  other  sub- 
stance which  intercepts  its  passage,  and  no  dew  or  frost  is 
formed.  Thus  plants  may  be  protected  against  frost  by 
covering  them  with  a  blanket  or  layer  of  straw :  the  same  end 
may  be  attained  by  raising  large  fires  by  means  of  damp  straw, 
brush,  <fec.,  so  as  to  destroy  the  transparency  of  the  air  by  a 
cloud  of  smoke  and  watery  vapor.  This  mode  is  practiced  by 
the  Incas  of  South  America,  who  seem  to  understand  the 
conditions  under  which  dew  and  frost  are  formed.  When 

*12 


138  SCIENTIFIC  AGRICULTURE. 

there  is  a  current  of  air,  there  will  be  no  condensation  of 
watery  vapor  so  as  to  form  dew  or  frost:  hence  they  are 
seldom  or  never  seen  on  a  windy  night. 

In  some  parts  of  the  world,  as  in  sections  of  South  America 
and  Mexico,  dews  are  so  copious  as  to  supply  the  place  of 
rains.  The  cold  ascribed  by  many  persons  to  the  light  of  the 
moon,  is  nothing  but  the  consequence  of  nocturnal  radiation. 
JMists,  fogs,  and  clouds,  are  only  floating  vesicles  of  watery 
vapor,  which  obscure  the  transparency  of  the  atmosphere; 
they  differ  only  in  the  degree  of  their  density.  "  A  fog,  [says 
a  celebrated  naturalist,]  is  a  cloud  in  which  one  is, — a  cloud  is 
a  fog  in  which  one  is  not"  Fogs  are  not  common  in  hot 
countries, — they  rise  to  a  small  height,  and  are  prevented  by 
winds.  In  Peru  dense  fogs  continue  for  half  the  year.  Day 
fogs  are  volcanic  ashes  and  vapors  diffused  through  the  air  by 
wind.  The  appearances  of  clouds  may  be  changed  according 
to  their  height,  density,  distance,  and  the  angles  at  which  the 
sun's  light  strikes  upon  them,  &c.  They  are  moved  about 
and  broken  apart  by  winds,  and  assume  various  and  beautiful 
hues,  according  to  the  different  colors  of  the  sun's  rays  which 
they  reflect 

Clouds,  then,  are  merely  floating,  distant  fogs,  and  arc  most 
frequently  formed  over  some  body  of  water  or  wet  soil, 
sxow. 

Snow  is  congealed  water,  which  descends  from  the  upper 
regions  of  the  atmosphere.  The  precise  conditions  of  atmos- 
phere requisite  for  its  formation,  or  the  manner  in  which  it 
takes  place,  is  not  yet  well  understood.  The  most  that  is 
known  respecting  it,  is  in  relation  to  the  form  of  its  flakes: 
these  are  stellate,  and  composed  often  of  hexagonal  prisms, 
arranged  at  an  angle  of  60°,  from  each  of  which  others  fre- 
quently shoot  out  at  the  same  angle.  The  whiteness  of  snow 
is  said  to  depend  on  the  minuteness  of  its  crystals.  In  some 
cases  snow  presents  no  appearance  of  crystalization. 


METEOROLOGY. 


139 


Snow  recently  fallen  has  a  bulk  ten  or  twelve  times  that  of 
the  water  from  which  it  is  formed ;  while  common  ice  has  a 
bulk  only  about  one-ninth  greater  than  the  water  of  which  it 
is  formed.  The  temperature  of  the  air  in  which  snow  is 
formed,  must  be  below  freezing, — that  is,  32°  Fah. ;  and  if  it 
falls  through  a  warmer  temperature  in  its  descent  to  the  earth, 
it  is  melted, — hence  there  is  no  snow  in  warm  weather,  nor  in 
the  torrid  zone,  except  on  the  summits  of  mountains  which 
reach  above  the  line  of  perpetual  congelation.  It  may  there 
snow  above  and  rain  below. 

The  snow  line,  or  line  of  perpetual  snow,  varies  greatly  in 
altitude,  according  to  location  and  circumstances.  On  the 
Himmalaya  chain,  according  to  Humboldt,  the  snow  line  on 
the  south  side  is  4,4000  feet  below  that  on  the  north  side ;  so 
that  this  line  cannot  be  depended  upon  as  a  point  by  which  to 
estimate  the  altitude  Of  mountains. 


[This  figure  from  Muller  shows  a  few  of  the  forms  of  snow  flakes  or 
crystals,  all  of  which  belong  to  the  hexagonal  system.] 


SCIENTIFIC    AGRICULTURE. 
HAIL. 

Hail  is  a  well  known  meteor,  which  occurs  most  commonly 
in  spring  and  summer,  and  is  often  accompanied  with  thunder. 
It  is  formed  by  the  congelation  of  rain  or  vapor  in  the  upper 
regions  of  the  atmosphere.  Hail  storms  are  of  rare  occurrence, 
and  seldom  continue  more  than  a  quarter  of  an  hour.  Hail 
clouds  always  float  lower  than  rain  clouds.  Hail  stones  appear 
to  be  composed  of  several  spherules  adhered  together;  those 
of  the  centre  being  soft,  sometimes  nearly  fluid  water,  and 
those  of  the  circumference  solid  and  opake. 

They  are  also  occasionally  laminated  or  radiated.  Hail 
stones  are  sometimes  enormously  large :  the  largest  of  which 
we  have  seen  any  account,  according  to  Dr.  Brande,  measured 
14  inches  in  circumference,  and  weighed  from  5  to  13  ounces. 
Many  ingenious  speculations  have  been  made  to  account  for 
the  formation  of  hail,  but  none  of  them  sufficiently  satisfactory 
to  be  entitled  to  implicit  belief.  The  most  probable  cause  of 
this  phenomenon  now  is,  that  "  hail  is  produced  by  the  mixture 
of  exceedingly  cold  air  with  a  body  of  hot  and  humid  air." 

[Olmstead. 

Whether  a  cold  wind  comes  suddenly  from  the  regions  of 
perpetual  congelation,  in  contact  with  a  body  of  hot  air  charged 
with  vapor,  blows  suddenly  into  the  regions  of  perpetual  frost, 
and  thus,  by  condensation  of  the  vapor,  produces  hail,  we  can- 
not determine.  It  is  sufficient  for  this  theory,  that  hot  moist 
air  meets  with  intensely  cold  air  in  any  way  whatever. 

LIGHTNING. 

"  This  is  an  electric  phenomenon  produced  by  the  passage 
of  electricity  between  one  cloud  and  another,  or  between  a 
cloud  and  the  earth."  The  zigzag  form  of  the  flash,  the  fre- 
quency of  its  repetition,  and  the  great  length,  or  extent  of  sky 
which  it  embraces,  are  not  yet  well  understood  or  accounted 
for. 


METEOROLOGY.  141 

The  phenomena  of  lightning  are  best  observed  from  the  tops 
of  mountains  which  extend  above  the  clouds;  from  such  a 
position  the  flashes  have  been  obsevered  to  extend  for  several 
miles  in  length.  The  frequency  of  succession,  and  length  of 
the  luminous  streaks,  are  supposed  to  depend  upon  the  imper- 
fect conducting  power  of  the  clouds  and  vapor  between  them. 

The  question  is  now  settled,  that  lightning  rods,  by  con- 
ducting off  the  fluid,  serve  as  a  protection  to  buildings.  The 
rod  protects  a  circle,  the  diameter  of  which  is  four  times  the 
length  it  extends  above  the  highest  point  of  the  building: 
hence  the  failures  of  lightning  rods  have  been  owing  to  their 
not  extending  sufficiently  high. 

THUNDER. 

The  noise  produced  by  the  passage  of  lightning  or  electricity 
through  the  air,  from  one  cloud  to  another,  or  from  a  cloud  to 
the  ground,  is  termed  in  common  language,  thunder.  The 
.loudness  of  thunder  depends  upon  the  magnitude  and  prox- 
imity of  the  explosion,  the  .relative  position  of  the  clouds,  the 
character  of  the  surrounding  country,  and  the  position  of  the 
observer. 

The  sharp  crashing  noise  sometimes  heard,  is  caused  by 
lightning  striking  near  us :  the  low  rumbling  noise  is  the  effect 
of  distant  thunder :  the  rattling  sound  is  occasioned  by  a  quick 
succession  of  explosions  from  a  highly  charged  cloud.  The 
same  species  of  snapping  noise  attends  the  discharge  of  sparks 
from  the  prime  conductor  of  a  charged  electrical  machine. 
"And  when  we  consider  how  trifling  a  portion  of  electric 
matter  is  put  in  action  by  the  most  powerful  means  of  artifi- 
cial excitement,  compared  with*  the  quantity  stored  up  in  a 
full  charged  thunder  cloud,  the  discrepancy  between  the 
appalling  crash  of  the  one  and  the  insignificant  snap  of  the 
other,  it  will  appear  surprising  that  both  should  originate  in 
the  same  cause." — [Brande.] 

Lightning  is  the  light  attendant  upon  electrical  action,  and 


142  SCIENTIFIC    AGRICULTURE. 

thunder  the  noise  which  succeeds  it:  the  difference  in  time 
between  the  two  phenomena  depends  upon  the  distance  of  the 
explosion  from  the  observer,  allowing  the  velocity  of  sound  to 
be  1,125  feet,  and  that  of  light  about  200,000  miles  in  a 
second  of  time.     We  give  below  an  extract  from  the  "  Ency- 
clopedia  Brittanica,"   showing   the  various   conditions  under 
which  electricity  appears  in  the  atmosphere. 
"1.  In  regular  thunder  clouds. 
"  2.  During  fog  with  small  rain. 
"  3.  During  a  brisk  snow  or  hail  storm. 
"  4.  During  a  smart  shower  on  a  hot  day. 
"  5.  During  a  shower  on  a  cold  day. 
"  6.  In  hot  weather  after  wet  days. 
"  7.  In  wet  weather  after  dry  days. 
"  8.  In  clear  and  frosty  weather. 
"  9.  In  clear  warm  weather. 
"  10.  During  a  cloudy  sky. 
"11.  During  a  mottled  sky. 
"  12.  In  sultry  weather  with  light  hazy  clouds. 
"  13.  In  cold,  damp  nights. 

"  14.  During  a  north-west  wind,  which  produces  a  sensation 
of  dryness  and  coldness,  not  indicated  by  the  thermometer." 

WINDS. 

Wind  is  air  put  in  motion.  Rarefaction  of  one  portion  of 
the  atmosphere  by  heat,  and  condensation  of  another  portion 
by  cold,  are  the  principal  causes  of  wind.  Some  local  causes 
of  limited  extent  may  produce  wind, — such  as  large  fires,  &c ; 
but  these  winds  are  limited  to  the  locality  where  they  origi- 
nate. There,  is  no  known  cause,  besides  heat  and  cold,  which 
is  capable  of  producing  any  general  or  extensive  current  in  the 
air. 

A  wind  may  be  merely  relative  or  apparent,  and  proceed 
from  the  passage  of  the  observer  through  the  air,  as  by  a 
steam  car  or  balloon.  If  the  speed  of  his  vehicle  be  twenty 


METEOROLOGY.  143 

miles  an  hour,  he  feels  a  current  of  air  equal  in  velocity  to  his 
own ;  the  wind  appears  to  blow  at  that  rate.  The  direction  of 
winds  may  be  modified  by  various  causes:  when  two  or  more 
currents  meet  from  different  directions,  the  general  direction 
will  be  a  resultant  one,  the  consequence  of  the  several  forces, 
as  in  the  case  of  trade  winds. 

Winds  have  received  various  distinctive  appellations  accord- 
ing to  the  phenomena  which  they  present :  thus  we  have  the 
trade  winds,  the  land  and  sea  breezes*  the  harmattan,  the 
monsoon,  the  simoon,  the  sirocco,  whirlwind,  hurricane  and 
tornado.  A  brief  description  only  of  each  of  these  varieties 
can  here  be  given. 

Land  and  sea  breezes. — These  winds  prevail  mostly  among 
the  islands  of  the  torrid  zone ;  but  more  or  less  in  all  maritime 
countries.  They  are  mild,  balmy  breezes,  which  blow  towards 
the  shores  during  the  day,  and  from  off  the  land  towards  the 
sea  during  the  night  time.  Their  phenomena  is  explained  as 
follows :  during  the  day  the  land  becomes  heated  by  the  rays 
of  the  sun, — the  heat  of  the  ground  rarifies  the  air,  which 
consequently  rises  to  the  higher  regions,  while  the  cold  air 
from  off  the  ocean  rushes  in  to  supply  its  place ;  thus  producing 
a  breeze  inland  as  long  as  the  sun  continues  to  warm  the  earth. 
This  is  called  the  sea  breeze. 

During  the  absence  of  the  sun,  the  earth,  which  radiates  its 
accumulated  heat  faster  than  the  sea,  becomes  cooler,  and  the 
direction  of  the  breeze  is  changed :  the  air  from  off  the  ocean 
rises,  while  the  colder  air  from  the  land  rushes  in  to  supply  its 
place,  just  as  in  the  case  of  the  sea  breeze.  This  night  wind 
which  blows  off  the  land  is  called  the  land  breeze.  As  the 
central  part  of  an  island  becomes  warmer  than  its  shores,  the 
breeze  will  be  the  strongest  in  the  midland :  "  its  current  will 
also  be  performed  in  a  constant  gyration;  so  that  the  air  which 
flows  in  upon  the  land  by  day,  rises,  flows  out  above,  and 
returns  again  in  the  same  current :  and  the  process  is  similar 


144  SCIENTIFIC   AGRICULTURE. 

by  night,  only  the  current  is  reversed."  At  the  time  when  a 
perfect  equilibrium  exists  between  the  temperature  of  the  land 
and  sea,  the  wind  ceases,  and  there  is  for  a  time  a  dead  calm. 

Trade  winds  are  produced  by  the  same  causes  operating 
upon  a  larger  scale,  and  the  revolution  of  the  earth  on  its  own 
axis.  These  are  tropical  winds,  which  prevail  only  within  the 
limit  of  about  30°  each  side  of  the  equator.  Their  general 
course  on  the  north  side  of  the  equator,  is  from  north-east  to 
south-west, — and  on  the  south  side,  from  south-east  to  north- 
west. The  upward  current  of  the  air  at  the  equator,  in  conse- 
quence of  its  higher  temperature,  causes  the  colder  air  to  rush 
in  from  the  north  and  south  towards  the  point  of  greater  rare- 
faction; this  produces  the  northward  and  southward  currents. 
These  currents  have  now  a  westerly  tendency  given  them  by 
the  diurnal  rotation  of  the  earth  on  its  axis  towards  the  cast; 
thus  producing  their  general  directions  as  above  described. 
When  not  changed  by  local  causes,  their  direction  is  the  same 
throughout  the  year :  but  however  they  may  be  modified,  they 
always  blow  towards  the  point  of  greatest  rarefaction,  and 
receive  a  relative  motion  from  the  earth's  diurnal  revolution. 
Their  velocity  is  greatest  at  the  equator,  where  the  earth's 
motion  is  the  most  rapid,  and  diminishes  towards  the  poles  in 
proportion  as  the  circumference  of  the  earth  diminishes,  and 
the  motion  is  less  rapid. 

The  harmattan  wind  is  a  periodical  easterly  wind,  which 
olows  irregulary  in  Africa:  it  occurs  three  or  four  times 
yearly,  and  continues  for  a  longer  or  shorter  period,  according 
to  circumstances.  It  blows  with  only  a  moderate  velocity, 
is  peculiarly  dry  and  unpleasant :  it  is  attended  by  a  haziness 
of  the  atmosphere,  which  often  obscures  the  sun  most  of  the 
day.  During  this  wind  there  is  no  moisture  in  the  air,  and  no 
dew  or  fog;  vegetation  becomes  parched,  and  droops.  Not- 
withstanding the  depressing  and  disagreeable  effects  of  the 
harmattan,  it  is  said  to  be  a  salubrious  wind. 


METEOROLOGY.  145 

Monsoons  are  a  modification  of  the  trade  winds,  which  occur 
mostly  in  the  Indian  ocean,  and  north  of  10°  south  latitude. 
The  south-east  winds  blow  from  April  to  October,  and  are 
frequently  attended  by  rain :  from  October  to  April  they  blow 
from  the  north-east,  and  are  dry.  The  change  from  one 
monsoon  to  another  is  usually  attended  by  violent  storms. 

The  simoon  is  a  hot,  pestilential  wind,  which,  during  certain 
seasons  of  the  year,  blows  northward  from  the  deserts  of  Africa 
and  Arabia.  This  wind,  after  being  modified  by  passing  over 
the  Mediterranean  sea,  is  called  in  the  south  of  Italy,  the 
sirocco;  its  poisonous  effects  are  supposed  to  depend  on  its 
dry  ness. 

Whirlwinds  are  such  as  have  a  rapid  gyratory,  as  well  as 
progressive  motion.  Hurricanes  are  generally  whirlwinds  con- 
fined to  a  narrow  path,  with  a  forward  motion,  sometimes  not 
exceeding  15  miles  an  hour. 

A  wind  which  moves  at  the  rate  of  4  or  5  miles  an  hour  is 
called  a  gentle  breeze;  when  its  velocity  is  15  or  20  miles  an 
hour,  it  is  a  gale;  when  30  to  40  miles  an  hour,  a  high  wind; 
and  when  100  miles  an  hour,  a  hurricane  or  tornado,  Hurri- 
canes are  more  frequent  on  the  shores  of  China  and  the  Indies 
than  in  any  other  part  of  the  world. 

13 


CHAPTER  III. 


AURORA   BOREALIS. 

"Tins  is  a  luminous  meteor  usually  appearing  in  tlie  northern 
part  of  the  sky,  and  presenting  a  light  somewhat  resembling 
the  dawn  or  break  of  day."  The  aurora  exhibits  such  a  variety 
of  forms  at  different  times,  that  no  general  description  can  give 
any  definite  idea  of  its  appearance:  this,  however,  may  be 
easily  attained  by  observation  of  the  meteor  itsel£  It  appears 
to  be  a  horizontal  cloud  extending  towards  the  east  and  west, 
and  rising  a  few,  degrees  above  the  horizon.  The  lower  part 
of  the  cloud  is  often  darkish,,  and  the  upper  part  lu.minous  and 
whitish:  from  this  part,  streams  or  columns  of  light  shoot 
upwards  with  an  unsteady,  wave-like  motion,  reaching  some- 
times to  the  zenith,  and  at  others  only  a  few  degrees  above  the- 
horizon. 

The  "Northern  Lights"  usually  appear  two  or  three  hours,, 
or  soon  after  sunset,  and  continue  a  few  hours,  and  occasionally 
the  whole  night :  they,  also  sometimes  appear  for  several  sue-  - 
cessive  nights,  but  are  rarely  seen  after  midnight  or  in  the 
morning. — [Brande.]    They  often  succeed  a  change  of  weather 
from  heat  and  rain  to  cold  and  clear.     They  are  sometimes 
tinged  with  .green  ;or  orange,  but  more  commonly  with  various 
shades  of  red.;    The  aurora  is  sometimes  seen  in  the  southern \ 
hemisphere.    The  mean  height  of  the  luminous  sheet  has  been  • 
variously  estimated  a^  from:100  to  400  miles.    No  satisfactory. 


MKTEOROLOGr.  147 

explanation  of  this  phenomenon  has  yet  been  given;  many 
ingenious  theories  have  been  proposed,  but  as  we  have  not 
space  to  detail  them  for  the  gratification  of  the  curious,  we 
must  refer  them  to  larger  and  more  scientific  treatises.  The 
probable  cause,  however,  is  electricity. 

IGNUS   FATUUS,    OR   "WILL   O*    THE    WISP." 

This  is  a  nocturnal  light,  commonly  known  in  this  country 
by  the  name  of  "  Jack- Lantern:"  it  is  seen  floating  over 
marshy  grounds,  moors,  grave  yards,  and  along  the  margins 
of  rivers,  and  sometimes  has  a  progressive  motion,  which  is 
probably  given  it  by  the  passing  breezes.  The  origin  and 
nature  of  this  meteor  have  been  the  subject  of  many  supersti- 
tious theories  and  absurd  speculations;  it  has  often  been 
ascribed  to  supernatural  causes.  The  most  probable  explana 
tion  of  it  is  that  given  by  Muller :  he  supposes  it  to  be  hydro- 
gen gas  which  is  mixed  with  phosphorus;  and  that  conse- 
quently it  is  nothing  more  than  a  phosphorescent  light. 

A  HALO, 

Is  a  luminous  circle,  usually  of  various  and  beautiful  hues, 
surrounding  the  sun  or  moon  during  certain  conditions  of  the 
atmosphere.  There  are  two  kinds  of  halo,  depending  upon 
different  physical  causes.  The  first  are  small,  their  diameter, 
according  to  Dr.  Brande,  not  exceeding  from  5°  to  10°,  and 
composed  of  three  or  more  concentric  rings  of  different  colors. 
"  These  are  usually  called  coronce;  and  they  appear  either 
when  a  small  quantity  of  aqueous  vapor  is  diffused  through 
the  atmosphere,  or  when  light  fleecy  clouds  pass  over  the  sun 
or  moon."  The  second  kind  consists  of  a  single  luminous 
circle  whose  diameter  is  about  45°. 

A  halo  of  the  moon  is  usually  a  white  circle  with  its  inner 
edge  sometimes  tinged  with  pale  red.  There  is  much  truth 
in  the  remark,  that  a  dense  halo  close  to  the  moon  portends 
rain.  Lunar  halos  are  most  frequent,  because  the  sun's  rays 


148  SCIENTIFIC    AGRICULTURE. 

arc  too  dazzling  to  admit  of  their  being  seen.  The  most 
probable  cause  of  this  phenomena  is,  that  it  depends  on  the 
refraction  of  light  in  passing  through  small  transparent  prisms 
of  ice,  floating  in  the  higher  regions  of  the  atmosphere. 

PARHELIA. 

Parhelia,  or  mock  suns,  consist  of  the  simultaneous  appear- 
ance of  several  images  of  the  true  sun.  They  are  at  the  same 
height  above  the  horizon  as  the  sun,  and  are  connected  by  a 
horizontal  circle,  which  is  sometimes  colored,  but  usually  white- 
The  cause  of  these  suns  is  not  satisfactorily  explained :  they 
are  supposed,  however,  to  depend  in  some  way  upon  the  reflec- 
tion and  refraction  of  the  sun's  rays.  There  may  be  parhelia 
without  rings,  and  rings  without  parhelia.  They  never  appear 
in  an  unclouded  sky, — sometimes  occur  opposite  to  the  sun. 

FIRE    BALLS. 

These  are  "luminous  bodies  which  suddenly  appear  in  the 
sky,  usually  at  a  great  height  above  the  earth,  and  shoot 
through  the  heavens  with  immense  velocity,  and  are  sometimes 
accompanied  by  the  fall  of  an  aerolite."  Various  hypotheses 
have  been  proposed  to  account  for  these  meteors :  limit  does 
not  admit  of  a  detail  of  these  opinions ;  and  it  is  perhaps  suffi- 
cient to  say,  that  the  true  explanation  of  this  phenomenon  has 
not,  so  far  as  we  can  ascertain,  been  given. 

RAINBOW. 

This  well  known  and  beautiful  meteor  consists  of  two  con- 
centric arches,  formed  of  the  colors  of  the  solar  spectrum.  It 
is  caused  by  the  refraction  and  reflection  of  the  sun's  rays 
while  falling  on  drops. of  rain.  The  size  of  a  rainbow  depends 
upon  the  height  of  the  sun  above  the  horizon.  Inverted  bows 
are  sometimes  seen  on  the  ground;  they  are  formed  by  the 
rays  of  the  sun  falling  on  the  drops  of  dew  or  rain  which  are 
suspended  from  the  tops,  of  grass,  or  from  spider'  webs :  they 


METEOROLOGY.  149 

are  also  seen  about  waterfalls  and  ship  masts,  forming  a  perfect 
circle.  Lunar  rainbows  are  sometimes  seen  in  the  night  time ; 
but  their  colors  are  faint  and  indistinct  In  order  to  see  a 
rainbow,  we  must  face  a  cloud  and  turn  our  back  to  the  sun 
or  moon.  The  philosophical  explanation  of  rainbows  will  be 
found  in  works  on  natural  philosophy  and  meteorology. 

MIRAGE. 

Mirage  is  an  optical  illusion  often  observed  at  sea,  especially 
in  high  latitudes ;  it  sometimes  also  appears  on  the  land,  par- 
ticularly in  Egypt  and  Persia:  it  is  seen  also  on  the  margins 
of  rivers  and  lakes.  It  consists  in  the  appearance  in  the  air 
over  the  surface  of  the  sea,  of  multiplied  images  of  objects  on 
the  surrounding  coast 

"  It  arises  from  unequal  refraction  in  the  lower  strata  of  the 
atmosphere,  and  causes  remote  objects  to  be  seen  double,  as  if 
suspended  in  the  air."  These  images  are  sometimes  inverted: 
ships,  whale  fisheries,  and  other  objects,  are  sometimes  descried 
by  means  of  mirage  at  considerable  distances.  The  mathe- 
matical theory  of  this  phenomenon  will  be  found  in  works  on 
optics,  &c. 

SHOOTING   STARS. 

These  are  common  and  well  known  meteors,  some  of  which 
resemble  fire  balls  in  every  respect.  We  shall  not  attempt 
any  description  or  explanation  of  them,  as  their  origin  and 
nature  are  involved  in  great  obscurity  and  uncertainty. 

AEROLITES. 

These  are  mineral  masses  which  fall  to  the  earth  apparently 
from  the  upper  regions  of  the  atmosphere.  They  have  a  dark 
or  blackish  color  externally  and  a  grayish  hue  internally. 
They  have  a  specific  gravity  more  than  three  times  that  of 
water :  chemical  analysis  of  one  specimen  shows  its  constituent 
elements  to  be,  iron,  sulphur,  silex,  nickel,  magnesia,  and  some- 
times chromium.  These  meteors  have,  with  some  probability, 

*13 


150  SCIENTIFIC   AGRICULTURE. 

been  supposed  to  come  from  volcanoes  in  the  moon :  but  there 
is  still  great  obscurity  hanging  about  the  whole  subject 

COLOR    OF    THE    SKY. 

The  general  color  of  the  unclouded  sky  is  azure  or  blue: 
this  is  explained  on  the  supposition  that  the  particles  of  the 
atmosphere,  when  illuminated,  reflect  mostly  the  blue  rays. 
Whenever  the  prevailing  color  of  the  sky  is  anything  but  a 
pure  blue,  it  is  discolored  by  smoke,  vapor  and  clouds;  the 
more  dense  these  clouds,  the  nearer  the  color  -of  the  sky 
approaches  to  black.  The  deep  red  of  the  morning  and 
evening  sky  is  explained  by  supposing  the  atmosphere  permits 
only  the  red  and  yellow  rays  to  pass,  and  reflects  the  blue 
rays. — [Muller.] 

The  fiery  red  of  morning  is  caused  by  an  excess  of  moisture, 
which,  notwithstanding  the  tendency  of  the  sun's  rays  to 
disperse  it,  forms  clouds  in  the  atmosphere,  and  hence  indi- 
cates rain.  A  gray  sky  at  morning  and  a  red  sky  at  evening, 
on  the  contrary,  foretell  fine  weather.  The  various  other 
beautiful  hues  which  tint  the  sky  and  fringe  the  massive 
clouds,  so  as  to  produce  all  the  varied  gorgeous  drapery  of 
the  heavens,  are  caused  by  the  absorption,  refraction  and 
reflection  of  the  different  rays  of  the  solar  spectrum. 

TWILIGHT. 

Twilight  is  the  diminished  light  of  day,  which  is  seen  from 
the  setting  of  the  sun  on  its  sinking  below  the  western  hori- 
zon, till  the  last  faint  gleaming  of  day  has  disappeared.  The 
time  at  which  twilight  begins  and  ends,  is  altogether  arbi- 
trary, and  must  depend  very  much  on  the  acuteness  of  the 
vision  of  the  observer.  It  has  been  said  to  commence  at  the 
moment  of  sunset,  and  terminate  when  the  first  small  stars 
are  visible.  Twilight  is  short  in  countries  having  a  pure  sky : 
in  Chili,  it  lasts  only  a  few  minutes.  In  high  latitudes  it  is 


METEOROLOGY.  151 

of  longer  duration,  on  account  of  the  sun's  orbit  being  much 
inclined  to  the  horizon.  In  countries  lying  in  the  vicinity  of 
50°  of  latitude,  twilight  continues  until  the  sun  has  descended 
from  15°  to  20°  below  the  horizon. 

The  moon's  light  is  only  the  reflected  light  of  the  sun,  and 
is  estimated  to  be,  when  in  its  greatest  intensity,  only 
part  as  much  as  the  light  of  that  vast  luminary. 


i 


PART    V. 


AGRICULTURE 


CHAPTER  I. 


FORMATION    AND    ELEMENTS    OF    SOILS. 

THE  soil  is  composed  of  disintegrated  rocks,  animal  and 
vegetable  matters :  most  soils  are  made  up  of  successive  layers 
of  fine  sand  and  organic  matters,  loam,  fine  gravel,  clay,  coarse 
gravel,  and  occasional  masses  of  rock  of  various  sizes.  Various 
causes  have  concurred  to  produce  the  alluvial  deposit  on  the 
surface  of  the  earth,  which  must  ultimately  have  been  formed 
entirely  of  the  rocks  which  constitute  the  solid  basis  and  prin- 
cipal bulk  of  the  globe. 

The  running  water  of  rivers  and  the  great  ocean  current 
which  sweeps  across  the  earth  had  denuded  the  rocks  which 
it  washed  in  its  course  from  the  high  Lpds  to  the  plains  and 
valleys :  in  this  way,  ravines  have  been  excavated,  valleys  filled 
up,  and  vast  level  plains  formed.  The  floods  formed  by  rains, 
and  the  torrents  resulting  from  melted  snow  and  ice,  which 
flow  down  the  mountains'  sides,  wash  away  all  loose  matters, 
and  often  undermine  and  tear  away  fragments  of  rock :  these 


154  SCIENTIFIC    AGRICULTURE. 

are  swept  along  by  the  impetuous  stream,  tlieir  corners  worn 
off,  and  they,  together  with  the  finer  particles,  are  deposited 
on  the  plains  or  in  the  valleys,  in  the  form  of  sand,  gravel  and 
"boulders." 

The  action  of  the  air  contributes  powerfully  to  the  decompo- 
sition and  crumbling  of  rocks.  Water,  also,  which  falls  into 
the  cleavage  or  crevices  of  rocks,  and  becomes  frozen,  often 
cleaves  large  masses  asunder  by  its  expansion  in  passing  into 
ice :  these  masses  are  again  subdivided  in  the  same  manner* 
until  entire  hills  of  marble,  slate,  and  other  rocks, 'are  com- 
pletely pulverized.  The  affinity  of  the  gases  of  the  air  and 
water  for  these  elements  of  the  various  rocks  produce  the  same 
effect.  The  combined  action  of  ice  and  water  in  transporting 
masses  of  rock  is  another  powerful  agency  in  the  formation 
and  distribution  of  soils.  Immense  blocks  of  rocks  are  fre- 
quently frozen  into  ice,  which  is  subsequently  broken  up  and 
floated  by  streams  and  freshets  to  great  distances  from  their 
original  locality :  these,  in  process  of  time,  become  pulverized, 
and  add  their  elements  to  the  soil. 

The  action  of  fire  in  volcanic  districts  produces  immense 
effects  in  chaging  the  character  of  rocks,  leveling  hills,  and 
filling  up  valleys  with  ashes  and  lava:  so  vast  is  the  quantity 
sometimes  thrown  out  at  a  single  eruption,  that  the  whole 
country  for  many  miles  around  is  covered  with  the  melted 
rocks,  scoria,  ashes  and  cinders. 

In  this  way  Pompeii,  Herculaneum  and  Stabia  were  inhumed 
A.  D.  79,  by  a  single  eruption  of  Vesuvius.  Whole  strata  of 
rocks  are  sometimes  broken  up  by  earthquakes,  and  are  after- 
wards disintegrated  and  mingled  with  the  soil.  The  agency 
of  winds  in  wafting  fine  particles  of  alluvium  and  sand  has  in 
many  places  entirely  changed  the  character  of  the  soil;  in 
some  places  vast  barren  plains  have  keen  formed,  "  dunes  "  or 
sand  hills  raised,  fertile  fields  stript  of  alluvium,  and  others 
coveted  by  sand  containing  no  other  elements  of  a  fertile  soil. 


SCIENTIFIC    AGRICULTURE.  155 

It  is  apparent  now,  that  the  soil  bears  no  necessary  resem- 
blance in  all  cases  to  the  rocks  on  which  it  lies,  except  when 
derived  directly  from  them ;  then  it  partakes  of  their  nature. 

After  the  surface  of  rocks  has  by  these  agencies  become 
sufficiently  pulverized  and  decomposed  to  form  a  thin  layer  of 
soil,  lichens  and  mosses  succeed  in  fixing  their  roots  in  it, 
causing  at  the  same  time  further  disintegration  of  the  rocks, , 
and  increase  of  the  soil"  by  their  annual  decay.      When  the- 
soil  becomes  in  this  way  of  sufficient  depth  and  fertility  to 
nourish  other,  larger,  and  more  perfect  species  of  plants,  vegetai- 
tion  becomes  more  abundant:  the  decay  of  this,  together  with; 
the  organic  and  earthy  matters  of  animals,  which  are  returned 
to  the  soil,  combined  with  the  art.  and  industry  of  man, — a 
soil  sufficiently  deep  and  fertile  for  successful  cultivation,  is  in« 
process  of  time  produced. 

A  general  knowledge  of  the  rocks,  metals  and  earths,  is  of 
great  value  to  the  agriculturist,  in  enabling  him,  by  the  indi-- 
cations  which  they  afford,  to  discover  springs,  mineral  waters, 
ores,  mines  of  coal  or  metal,  marl,  lime,  valuable  stones,  &c. ; 
and  also  to  direct  him. to  the  best  locations  for  lime  kilns,  glass- 
houses, brick  kilns,  potteries,  foundries,;  salt  works,  bath  houses 
and  stone  quarries.  Modern  chemistry  has  shown  that  almost 
every  substance  is  a  compound  of  several  others, — and  future- 
experiment  may  yet  show  us  the  compound  nature  of  many 
bodies  which  are  now  considered  elementary.  There  would  be 
little  difficulty  in  determining  the  character  of  any  soil,  had  we 
only  to  consider  the  constitution  of  the  rock  from  which  it  was 
originally  derived. 

But,  during  the  lapse  of  ages,  the  various  causes  which  have 
been  in  operation  have  so  changed  them  that  their  primitive 
character  has  almost  disappeared,  and  they  must  be  considered 
in  thehvpresent  actual  conditions.  Arable  soils  consist  mainly 
of  silex  and  alumina,  with  some  lime,  iron,,  sodium,  potassium. 


156  SCIENTIFIC   AGRICULTURE. 

manganese,  magnesia,  animal  and  vegetable  remains  in  various 
proportions  and  different  stages  of  decomposition.  The  ele- 
ments of  the  soil  must  exist  in  different  proportions,  in  order 
to  render  them  available  for  agricultural  purposes. 


CHAPTER  II. 


METALS,  METALLOIDS,   AND    ORGANIC   ELEMENTS   OF 
SOILS. 


SILICON.* 

SILICON  is  one  of  the  most  abundant  and  widely  distributed 
substances,  constituting  probably  one  sixth  of  the  entire  mineral 
weight  of  the  globe.  It  is  never  found  pure  or  in  an  uncom- 
bined  state,  but  always  combined  with  oxygen,  forming  oxide 
of  silicon,  or  silicic  acid.  The  vast  mountains  of  granite,  gneiss, 
porphyry  and  sandstone, — mica,  feldspar,  crystal  quartz,  nearly 
all  precious  stones,  -the  sands  of  the  sea  shore  and  desert,  and 
all  stones  that  emit  sparks  on  being  struck  by  steel,  are  mainly 
silicon. 

It  is  contained  in  a  crystaline  state  in  the  outside  bark  of 
many  plants,  particularly  in  cane,  bamboos  and  the  grasses.  It 
is  with  difficulty  separated  from  its  oxygen, — but  when  sepa- 
rated and  pure,  it  is  a  fine  whitish  powder,  destitute  of  taste 
or  odor:  it  undergoes  no  change,  except  becoming  darker  and 
denser,  by  any  common  degree  of  heat,  but  melts  before  the 
blow  pipe  into  colorless  glass ;  it  has  no  affinity  for  pure  water, 
so  that  it  is  not  dissolved  in  it  in  the  smallest  degree ;  it  absorbs 

*  Recent  investigations  appear  to  show  that  silicon  is  neither  a  metal 
nor  a  metalloid. 

14 


158  SCIENTIFIC  AGRICULTURE. 

water  slowly,  and  allows  it  to  escape  easily.  It  is  neither  dis- 
solved nor  acted  upon  by  any  acid  except  the  fluoric, — with 
which  it  unites  find  forms  a  fluoride  of  silicon. 

The  equivalent  number  of  silicon  is  22.22,  —  its  specific 
gravity  2.GG.  The  fixed  alkalies  easily  unite  with  silicon,  and 
form  silicates,  as  the  silicate  of  potash,  lime,  <fcc.  It  forms  an 
important  ingredient  in  porcelain,  glass,  and  the  enamel  or 
glazing  of  stone  ware.  The  salts  of  silicon  are  not  numerous; 
they  are  all  insoluble  in  water,  (according  to  Prof.  Johnston,) 
except  those  of  potash  and  soda. 

As  silicon  is  so  important  an  element  in  plants,  and  so  inva- 
riably present  in  all  productive  soils,  a  knowledge  of  its  chemi- 
cal character,  and  the  best  means  of  rendering  it  available  to 
the  roots  of  growing  vegetation,  is  indispensable. 

ALUMINUM. 

This  metallic  earth  is  found  in  greater  abundance  in  nature 
than  lime,  being  one  of  the  principal  ingredients  in  nearly  all 
rocks,  except  the  purest  limestone :  it  is  the  principal  element 
of  clay,  and  exists  largely  in  garnet,  albite  and  mica:  it  is  found 
also  in  the  ashes  of  most  plants.  In  its  native  state  it  is  usually 
found  in  combination  with  silica,  and  sometimes  with  sulphuric 
or  phosphoric  acid:  it  is  also  found  nearly  pure,  or  uncombined, 
in  the  ruby  and  sapphire,  two  beautiful  precious  stones.  Alu- 
mina is  an  oxide,  and  the  only  one  known  of  the  earth  alumi- 
num ;  it  is  white,  tasteless  and  inodorous ;  its  equivalent  num- 
ber is  13.7. 

It  dissolves  in  acids  and  in  solutions  of  caustic  alkalies;  it 
has  a  strong  tendency  to  unite  with  organic  matters,  and  has 
fcbo  a  greater  affinity  for  water  than  any  of  the  other  elemen- 
tary earths.  "When  mixed  with  silica  in  the  proportion  to 
form  clay,  it  is  easily  molded  into  any  form,  as  in  stone  and 
earthen  ware:  it  loses  part  of  its  tenacity  by  fire,. — hence  the 
benefit  of  burning  clay  soils.  Alum  is  a  salt  formed  by  the 
union  of  potash,  alumina  and  sulphuiic  acid, — this  salt  is 


SCIENTIFIC  AGRICULTURE.  159 

extensively  used  as  a  mordant  in  calico  printing.  Alumina  is 
supposed  to  contribute  but  little  to  the  nourishment  of  plants: 
it  is  said  by  Liebig  to  be  an  absorbent  of  ammonia:  this, 
however,  is  doubted  by  Prof.  Johnston.  Its  principal  agency 
as  ji.i  element  of  soils,  is  of  a  mechanical  kind.  The  salts  of 
alumina  are  few;  they  have  not  been  sufficiently  tested  as 
fertilizers  to  determine  precisely  their  value  in  this  respect: 
Sprengol  considers  them  highly  deserving  of  trial  in  practical 
agriculture. 

MANGANESE, 

This  mjtal  is  diffused  widely  through  nature,  although  not 
in  great  abundance:  it  is  found  mostly  in  the  mineral, — but 
traces  of  it  also  exist  in  the  animal  and  vegetable  kingdoms. 
It  has  a  very  strong  affinity  for  oxygen,  and  is  therefore  with 
difficulty  reduced  from  its  oxides  and  ores, — which,  however, 
may  be  done  by  a  long  continued  and  intense  heat 

It  is  hard,  brittle,  granular,  grayish  white,  and  has  a  specific 
gravity  of  8 :  it  is  very  infusible,  soon  tarnishes  by  the  absorp- 
tion of  oxygon,  and  after  a  while  falls  into  a  black  powder. 
There  are  several  oxides,  two  acids,  and  many  salts  of  manga- 
nese, some  of  which  are  soluble  and  others  insoluble  in  water. 
It  is  used  in  the  arts,  and  is  probably  a  necessary  ingredient 
in  soils.  Its  equivalent  is  27.G7. 

IRON. 

This  is  the  most  important  of  all  the  metals,  and  is  the  most 
extensively  distributed  over  the  earth.  It  is  sometimes  found 
in  loose  blocks  of  pure  metal  on  the  surface ;  but  mostly  in 
veins  and  mines,  combined  with  sulphur,  forming  a  gold 
colored  ore,  called  sulphuret  of  iron, — and  with  oxygen  in  the 
form  of  the  black  and  red  oxides :  it  is  also  extensively  com- 
bined with  carbonic  acid,  constituting  the  clay  iron  ore.  Native 
arsenites,  phosphates,  sulphates  and  other  salts  have  been, 
found. 

Nearly  all  reddish  soils  and  stones  are  colored  by  oxide  of 


160  SCIENTIFIC    AGRICULTURE. 

iron.  Pure  iron  is  bluish  white,  brilliant  malleable  and  ductile, 
the  strongest  of  all  metals,  and  has  a  specific  gravity  of  7.8 ; 
its  equivalent  is  27.14. 

Iron  oxidizes  readily  when  in  contact  with  moisture,  and 
also  by  heat.  Only  two  of  the  oxides  are  of  any  interest  to 
the  agriculturist,  viz:  the  black  and  the  red.  The  black  oxide 
rarely  occurs  in  the  soil,  except  in  combination  with  some  acid ; 
and  this,  when  exposed  to  the  air,  absorbs  oxygen  and  changes 
to  the  red  oxide.  When  the  black  oxide  or  sulphate  is  present 
in  moist  boggy  soils,  it  proves  injurious  to  vegetation:  the  red 
is  less  injurious.  Both  are  insoluble  in  pure  water,  and  both 
are  soluble  in  acids.  The  red  oxide  is  said  to  absorb  ammonia 
from  the  atmosphere,  and  by  thus  bringing  it  within  the  reach 
of  plants,  it  is  in  this  way  useful,  when  the  soil  contains  any 
considerable  quantity. 

A  red  soil  containing  much  iron  should  be  turned  over  fre- 

iD 

quently,  so  as  to  keep  it  pervious  to  the  air ;  and,  according  to 
Johnston,  such  soil  "may  occasionally  be  summer  fallowed  with 
advantage,  in  order  that  the  oxide  may  absorb  from  the  air 
those  volatile  substances  which  are  likely  to  prove  beneficial 
to  the  growth  of  future  crops." 

The  sulphate  of  iron  (green  vitriol,)  is  often  found  in  soils, 
particularly  in  bogs  and  marshy  places,  and  it  is  said  to  be 
very  injurious  to  vegetation:  these  effects  are  counteracted  by 
lime,  marl,  and  plaster,  which  decompose  the  sulphate  and 
unite  with  the  sulphuric  acid  and  form  gypsum.  In  this  way 
it  is  beneficial  to  soils  containing  lime,  and  may  be  used  as  a 
manure.  Iron  is  found  in  the  ashes  of  nearly  all  plants,  and 
to  a  small  extent  in  animal  bodies.  It  is  probable  that  some 
of  the  soluble  salts  of  iron  are  requisite  to  the  growth  of  most 
plants. 

SODIUM. 

Sodium  exists  in  vast  quantities,  and  is  widely  diffused 
through  nature :  it  is  found  combined  with  chlorine,  forming 


SCIENTIFIC    AGRICULTURE.  1G1 

common  salt,  of  which  great  quantities  are  found  in  Poland, 
England  and  elsewhere.  It  is  the  principal  saline  ingredient 
in  the  waters  of  salt  lakes  and  the  ocean.  It  is  found  in  many 
minerals,  most  plants,  and  in  all  the  animal  fluids.  Sodium  is 
found  in  vast  quantities  in  South  America  in  the  form  of  a 
nitrate. 

The  pure  metal  -sodium  is  lighter  than  water,  its  specific 
gravity  being  0.972;  its  equivalent  number  is  23.3.  It  is  a 
silvery  white  metal,  resembling  potassium  closely  in  its  appear- 
ance. The  compounds  of  sodium  are  numerous  and  important 
This  metal  is  soft  at  common  temperatures,  melts  at  194°  F., 
and  oxidizes  rapidly  in  the  open  air. 

As  soda  exists  in  most  soils,  and  is  found  in  some  form  in 
most  if  not  all  plants,  it  is  probably  a  necessaay  ingredient  in 
soils ;  many  of  its  salts,  particularly  the  nitrate,  sulphate,  chlo- 
ride and  phosphate,  are  valuable  fertilizers. 

POTASSIUM. 

This  is  the  metallic  basis  of  potash :  it  is  bluish  white  when 
not  exposed  to  the  air,  but  by  the  contact  of  ajr  it  instantly 
oxidizes  and  becomes  covered  by  a  crust  of  the  alkali,  potash: 
when  thrown  in  water,  it  takes  fire  and  burns,  with  a  violet 
flame.  At  common  temperatures  it  is  soft  and  may  be 
molded  into  any  form,  like  wax:  "at  32°  it  is  quite  brittle, 
and  crytalizes  in  cubes;,  at  70°  it  is  pasty,  and  at  150°,  per- 
fectly liquid.  At  a  dull,  red  heat,  it  boils,  forming  a  green 
vapor,  and  may  be  distilled." 

Like  sodium,  it  is  lighter  than  water;  its  specific  gravity 
being  0.655.  Potassium  has  a  remarkable  affinity  for  oxygen, 
which  it  abstracts  from  almost  all  other  bodies.  Its  equiva- 
lent number  is  39.3.  Potash  is  a  strong  fixed  alkali:  it  neu- 
tralizes the  strongest  acids,  and  its  salts  are  numerous  and 
important  Potassium  is  not  found  in  an  uncombincd  and 
pure  state  in  nature,  but  in  the  form  of  an  oxide :  it  exists  in 

*H 


162  SCIENTIFIC    AGRICULTURE. 

many  minerals,  nearly  all  plants,  and  in  animal  bodies.  It  is 
most  abundant  in  the  green  and  tender  parts  of  plants, — the 
timber  of  forest  trees  contains  comparatively  little. 

Its  powerful  action  on  other  metals  and  earths,  its  caustic 
action  on  vegetable  substances,  and  its  almost  universal  pre- 
sence in  soils  and  vegetation,  show  it  to  be  an  indispensable 
element  of  good  soils,  and  a  powerful  fertilizer.  Potash  is 
rendered  more  caustic  by  mixture  with  quick  lime, — in  this 
way  it  is  beneficial  in  compost  by  facilitating  the  decomposition 
of  vegetable  matters. 

MAGNESIUM. 

Magnesium  is  found  in  the  minerals,  serpentine,  talc,  steatite, 
asbestos,  augite,  chrysolite  and  hornblende:  it  is  always  found 
combined  with  acids,  or  other  earths, — it  is  found  also  in  marl, 
and  in  small  quantities  in  animal  substances.  It  is  a  white, 
silver-like  metal  when  pure,  malleable,  and  fusible  at  a  red  heat, 
not  changed  by  dry  air,  but  slowly  oxidized  by  damp  air:  it 
dissolves  in  dilute  acids,  giving  off  hydrogen  gas,  and  forming 
a  salt  of  magnesia. 

Its  equivalent  number  is  12.7.  When  heated  to  redness  in 
the  air,  or  in  oxygen,  it  burns  with  brilliancy,  and  forms  mag- 
nesia, or  oxide  of  magnesium:  it  inflames  spontaneously  in 
chlorine.  It  exists  in  considerable  quantity  in  nature,  par- 
ticularly in  magnesian  limestone. 

Magnesia  slowly  but  entirely  neutralizes  acids ;  it  is  inodorous, 
white,  has  a  slightly  alkaline  taste,  absorbs  and  retains  water 
to  nearly  the  same  degree  as  lime,  but  is  less  caustic  and 
alkaline.  There  are  several  important  salts  of  magnesia,  some 
of  which  are  valuable  as  fertilizers,  and  indispensable  to  the 
growth  of  vegetation. 

CALCIUM. 

Calcium  is  a  white  silvery  metal,  heavier  than  water, — 
having  a  strong  affinity  for  oxygen,  with  which  it  combines 


SCIENTIFIC    AGRICULTURE.  103 

only  in  one  proportion,  forming  lime.  The  equivalent  number 
of  calcium  is  20.5. 

Lime  is  the  most  important  and  abundant  of  all  the  earths, 
being  extensively  distributed  through  the  mineral  kingdom, 
and  constituting  the  principal  earthy  ingredient  in  the  shells 
and  bones  of  animals,  and  also  existing  in  all  plants.  It  is 
found  in  nature  combined  with  carbonic  acid,  as  in  marble, 
limestone  and  chalk,  in  quantities  so  large  as  to  form  entire 
mountains.  It  is  found  combined  with  sulphuric  acid,  consti- 
tuting gypsum  or  plaster  of  paris:  it  is  also  combined  with 
phosphoric,  fluoric  and  arsenic  acids. 

The  minerals,  calcareous  spar,  gypseous  spar,  arragonite,  and 
many  others,  are  composed  of  lime.  All  natural  waters  con- 
tain more  or  less  of  this  earth.  Lime  is  a  pure,  white,  alkaline 
earth:  when  burned  lime  is  exposed  to  the  air,  it  rapidly 
absorbs  water,  and  falls  into  a  line  powder,  which  is  called 
"slaked  lime,"  or  hydrate  of  lime.  This  earth  has  a  strong 
affinity  for  acids,  with  which  it  forms  several  salts.  It  is  only 
sparingly  soluble  in  water,  and  less  so  in  hot  than  in  cold 
water :  when  completely  dissolved  in  clear  water,  it  is  called 
lime  water:  this,  when  exposed  to  the  air,  unites  with  the 
carbonic  acid  of  the  air,  and  a  thin  pellicle  or  layer  of  carbon- 
ate of  lime  is  formed  on  the  surface, — this  soon  falls  to  the 
bottom,  and  another  layer  is  formed ;  and  so  the  process  con- 
tinues until  the  lime  ail  becomes  a  carbonate,  and  is  thus 
precipitated  from  the  water. 

Lime  attacks  and  destroys  both  animal  tissues  and  vegetable 
substances  with  rapidity,  and  without  the  exhalation  of  those 
noxious  gases  and  offensive  odors,  which  result  when  putre- 
faction goes  on  without  the  presence  of  lime.  Lime  is  valua- 
ble as  a  manure  in  soils  destitute  of  this  earth,  by  supplying 
an  indispensable  element  to  plants,  and  also  by  neutralizing 
r.cidity,  dissolving  silica,  and  decomposing  insoluble  organic 


16-i  SCIENTIFIC    AGRICULTURE. 

m  liters,  such  as  woody  fibre,  humus,  peat,  ulmine,  <kc.      The 
salts  of  lime  arc  also  of  great  value  as  fertilizers. 

MARL. 

Marl  is  a  compound  of  lime  and  clay,  so  intimately  mixed 
that  their  respective  particles  cannot  be  distinguished.  The 
exact  process  by  which  nature  combines  the  two  elements  is 
not  known;  for  if  clay  and  lime  -be  mixed  together  artificially, 
they  form  a  substance  quite  different  from  natural  marl:  &nd, 
according  to  Timer,  "it  does  not  possess  the  faculty  of  losing 
its  aggregation  when  exposed  to  the  influence  of  the  atmos- 
phere, and  crumbling  to  dust  like  natural  marl." 

The  proportions  of  the  two  elements  are  various:  sometimes 
the  lime  predominates,  sometimes  the  clay,  and  in  some  speci- 
mens they  are  equal.  When  the  clay  predominates  greatly,  it 
is  called  clay  marl:  when  the  lime  predominates,  it  is  called 
Iim2  ra  ii-1.  M  irl  is  found  in  considerable  variety,  both  of  com- 
position and  color:  it  assumes  a  blue,  red,  yellowish  or  whitish 
hue,  according  to  the  oxides  of  iron,  or  other  matters  which  it 
may  contain :  it  is  found  in  greater  or  less  quantities  in  almost 
all  countries, — sometimes  on  or  near  the  surface,  and  in  other 
cases  at  considerable  depths  in  the  earth. 

"It  is  confined  [says  Dr.  Hitchcock,]  to  the  alluvial  and 
tertiary  strata,  and  differs  from  many  varieties  of  limestone, 
only  in  not  being  consolidated."  It  often  contains  salts  of 
potash  and  soda,  fragments  of  shells,  bones,  and  some  vegeta- 
ble matter:  that  which  contains  a  large  quantity  of  shells  is 
called  shell  marl:  several  other  species  of  marl  are  described, 
the  most  important  and  valuable  of  which  is  greenstone  marl 

Nearly  all  the  varieties,  except  stone  marl,  are  easily  pene- 
trated and  their  particles  separated  by  water:  frost  is  also  an 
active  agent  in  pulverizing  it, — it  is  therefore  often  laid  on 
land  at  the  beginning  of  winter.  Marl  may  be  detected  by 
the  acids,  with  which  it  effervesces  and  forms  salts.  It  is 
evident  from  the  character  and  composition  of  marl,  that  it  is. 


SCIENTIFIC    AGRICULTURE. 

a  valuable  fertilizer,  especially  on  lands  deficient  in  clay  and 

lime. 

GYPSUM. 

Gypsum  is  a  compound  of  sulphuric  acid,  lime  and  water: 
it  is  sometimes  found  in  the  form  of  a  soft  yellowish  white  rock, 
with  a  texture  resembling  that  of  loaf  sugar ;  "  but  sometimes 
[says  Lyell,]  it  is  entirely  composed  of  lenticular  crystals."  It 
is  insoluble  in  acids,  and  does  not  effervesce,  for  the  reason 
that  it  is  already  combined  with  sulphuric  acid,  for  which  it 
has  a  stronger  affinity  than  for  any  other.  A  variety  called 
anhydrous  gypsum  sometimes  occurs,  which  contains  no  water. 

Gypsum  is  nearly  insoluble  in  pure  water; — when  deprived 
of  its  water  by  heat,  it  is  called  calcined  gypsum,  or  "  plaster 
of  paris," — in  this  state,  if  mixed  with  water,  it  may  be  formed 
into  molds  or  casts,  and  it  soon  solidifies  into  a  hard,  white, 
compact  mass.  When  calcined  gypsum  is  long  exposed  to  the 
air,  it  absorbs  moisture,  and  is  no  longer  fit  for  casts  and  stucco 
work,  until  calcined  afresh.  Gypsum  can  only  be  fused  by  a 
high  degree  of  heat, — it  does  not  then  part  with  its  sulphuric 
acid,  but  only  loses  its  water.  The  origin  of  this  rock  is  diffi- 
cult to  explain ;  its  found  mostly  among  the  new  red  sandstone, 
but  occurs  also  among  other  rocks. 

It  is  found  in  most  countries  in  great  abundance,  and  in 
various  forms,  as  gypseous  spar,  gypseous  stalactites  and  sta- 
lagmites, compact  gypsum,  &c.,  and  in  combination  with  clay 
and  lime.  Gypsum  cannot  be  formed  artificially.  Water  con- 
taining gypsum  is  called  hard  water.  The  decomposition  of 
gypsum  can  be  easily  effected  by  the  alkaline  carbonates:  if 
powdered  gypsum  be  boiled  in  a  solution  of  carbonate  of 
potash,  a  double  decomposition,  and  also  reunion,  takes  palce ; 
the  sulphuric  acid  of  the  gypsum  unites  with  the  potash,  and 
forms  sulphate  of  potash,  while  the  carbonic  acid  unites  with 
the  lime  of  the  gypsum  and  forms  carbonate  of  lime.  Gypsum 
is  one  of  the  most  valuable  fertilizers  known. 


106  SCIENTIFIC    AGRICULTURE. 

CLAY. 

Clay  is  a  compound  of  the  t\vo  earths,  silica  and  alumina,  in  a 
state  of  chemical  union:  it  usually  contains,  also,  an  excess  of 
uncombined  silica  in  the  form  of  sand.  Proper  clay  is  formed 
by  nature  alone,  for  no  chemical  process  is  known  by  which 
silica  and  alumina  can  be  made  to  unite  so  as  to  form  real  clay. 
It  is  usually  colored  by  some  of  the  oxides  of  iron,  so  as  to 
present  a  bluish,  yellow,  red  or  brown  hue. 

The  two  elements  of  clay  are  rarely  contained  in  equal 
quantity ;  the  silica  almost  always  predominates, — sometimes 
to  the  amount  of  93  per  cent.  Clay  sometimes  contains  an 
insoluble  carbonate  or  phosphate  of  iron,  which  are  both 
thought  to  be  injurious  to  vegetation.  It  sometimes  contains 
also  manganese  and  sulphate  of  iron,  the  last  of  which,  unless 
in  a  limy  soil,  is  injurious  to  plants:  organic  matters  are  often 
found  in  clay,  giving  it  a  blackish  hue  and  astringent  properties. 
Clay  has  been  form  ad  by  the  decomposition  of  rocks,  such  as 
granite,  feldspar,  clay  slate  and  argillaceous  schist. 

Clay  which  contains  neither  iron  nor  vegetable  matter,  does 
not  change  color  by  heat:  if  it  contains  vegetable  matter,  it 
becomes  lighter  colored  by  heat;  if  colored  dark  by  oxide  of 
ircn,  it  may  become  lighter  by  burning,  on  account  of  the  iron 
changing  its  proportion  of  oxygen.  White  clay,  which  does 
not  change  color  by  heat,  is  nearly  or  quite  pure.  When  clay 
is  dry,  it  absorbs  water  rapidly,  becomes  tenacious  and  adhe- 
sive, so  as  to  retain  any  form  or  impression  given  to  it:  when 
saturated  with  water,  it  no  longer  allows  that  fluid  to  pass 
through  it:  it  is  from  this  cause  that  water  stands  long  on  the 
surface  of  the  ground  in  swamps  having  a  clay_  subsoil, — and 
this  is  why  we  find  springs  and  water  veins  before  we  come  to 
solid  rock. 

When  wet  clay  is  exposed  to  frost,  it  is  cracked  or  fissured, 
and  sometimes  completely  pulverized,  by  the  expansion  of  the 
water  it  contains,  during  freezing.  It  retains  water  with  more 


X 


SCIENTIFIC   AGRICULTURE.  107    - 

tenacity  than  any  other  earth,  and  after  being  deprived  of  its 
water  by- heat,  becomes  hard.  After  being  heated  to  red 
clay  loses  its  ductile  properties,  is  insoluble  in  water,  and  is  of 
no  use  in  the  soil,  urtil,  by  long  action  of  the  atmosphere, 
moisture,  and  animal  manure,  it  is  changed  to  its  former  con- 
dition. Clay  does  not  effervesce  with  acids,  unless  it  contains 
lime  or  carbonate  of  iron :  it  requires  a  high  degree  of  heat  for 
its  fusion.  Clay  is  often  found  in  combination  with  gypsum. 
There  are  several  varieties  of  clay,  of  which  we  notice  only  a 
few. 

Kaolin,  or  porcelain  clay,  is  the  purest  and  finest,  and  is 
used  in  the  manufacture  of  porcelain  ware:  it  is  of  a  yellowish 
or  grayish  white  hue,  and  is  supposed  to  be  formed  by  the 
decomposition  of  feldspar. 

Pipe  day  ranks  next  to  kaolin  in  fineness,  and  is  of  various 
hues. 

B^le  is  a  species  of  red  clay,  used  in  the  manufacture  of 
brown  earthern  ware. 

Potter's  clay  is  used  for  bricks  and  stone  ware. 
CLi'j  iron  ore  contains  carbonate  and  phosphate  of  iron,  and 
has  been  described  under  the  head  of  iron. 

TEAT. 

"Peat  usually  consists  of  soluble  and  insoluble  geine,  with 
a  mixture  of  undecomposed  vegetable  matter  and  some  earths." 
It  is  usually  limited  to  the  colder  parts  of  the  globe:  it  results 
mostly  from  the  accumulation  and  decomposition  of  mosses, 
but  also  from  any  other  vegetable  matters  which  become 
mixed  with  it 

The  lower  stratum  of  peat  beds  decays,  while  the  plants  on 
the  surface  continue  to  grow,  thus  adding  new  matter  annually 
until  they  attain  the  thickness,  in  some  cases,  of  thirty  or  forty 
feet.  In  tropical  climates,  the  heat  produces  decomposition  so 
speedily  that  vegetables  are  resolved  into  their  elements  before 
peat  can  be  formed. 


. 

1G8  SCIENTIFIC    AGRICULTURE. 

Pe.it  is  usually  found  also  in  low  boggy  or  marshy  districts. 
According  to  Dr.  McCulloch,  "by  the  long  continued  action  of 
water  and  other  agents,  the  geine  of  peat  is  changed  into  bitu- 
men and  carbon,  which  constitute  lignite  and  bituminous  coal : 
in  a  few  instances  the  process  of  bitumenization  has  been  found 
considerably  advanced  in  beds  of  peat." 

Peat  is  remarkable  for  its  power  of  preserving  animal  mat- 
ters from  putrefaction. 

The  following  is  an  analysis  of  a  specimen  of  peat  from 
Massachusetts. 

Soluble  geine,         -  26.00 

Insoluble  do.      -  -     59.60 

Sulphate  of  Lime,  -  -                     4.48 

Phosphate  of  do.  -         -         -         -       0.72 

Silicates,        -  9.20 

100.00 

When  the  decay  is  far  advanced,  the  peat  is  a  dark  colored 
and  sometimes  solid  mass;  when  less  advanped  in  decomposi- 
tion, it  is  light  brown,  spongy,  and  contains  pieces  of  vegeta- 
bles not  yet  disorganized, — in  this  state  it  is  used  in  some 
countries  as  fuel.  Peat  is  sometimes  sour,  from  the  presence 
of  phosphoric  and  acetic  acids :  it  sometimes  also  contains  am- 
monia; it  decomposes  slowly  in  the  open  air.  When  mixed 
with  lime  or  potash  and  fermenting  barn-yard  manure,  it 
becomes  a  valuable  fertilizing  agent,  and  may  be  used  on  any 
soil  which  requires  the  addition  of  vegetable  matter. 

HUMUS. 

Humus  is  a  brown  or  blackish  colored  substance,  composed 
of  vegetable  matter  in  a  state  of  decay.  "  Humus  [says  Bous- 
singault,]  is  the  last  stage  in  the  putrefaction  of  vegetable 
organic  matter :  its  elements  have  acquired  a  stability  which 
enables  them  to  resist  all  fermentation."  It  is  of  a  spongy 
texture,  easily  pulverized,  and  nearly  insoluble  in  water:  it 


SCIENTIFIC    AGRICULTURE.  169 

absorbs  water  with  such  avidity  as  to  contain  three  fourths  of 
its  own  weight  without  being  moist 

Weak  acids  have  little  effect  on  humus,  except  to  dissolve 
the  alkaline  and  metallic  or  earthy  matters  which  are  usually 
mixed  with  it  Potash  and  soda  dissolve  humus  entirely,  with 
the  evolution  of  ammonia:  from  this  solution,  acids  cause  a 
precipitate  of  a  brown  inflammable  powder  resembling  ulmine. 
Humus  contains  more  carbon  and  nitrogen  than  the  vegetables 
from  which  it  is  derived :  the  nitrogen  may  be  partly  formed 
from  the  excrements  of  insects  which  live  in  the  humus. 

Humus  contains,  besides  some  mineral  elements,  carbon, 
oxygen,  hydrogen  and  nitrogen,  phosphoric,  sulphuric  and 
humic  acids.  Humus  is  dissipated  when  exposed  to  the  air  by 
a  slow  combustion,  with  the  disengagement  of  carbonic  acid. 
This,  and  all  vegetable  earths,  are  entirely  destructible.  Salts 
are  formed  during  the  decomposition  of  humus,  by  the  union 
of  bases  with  the  humic  acid, — these  are  called  humates. 

Besides  the  above  elements,  humus  contains,  according  to 
Berzelius,  humic,  crenic  and  apocrenic  acids,  and  traces  of 
glairin.  Humus  is  an  indispensable  ingredient  in  all  fertile 
soils,  hence  the  necessity  of  replacing  it  in  the  soil  as  fast  as  it 
is  exhausted. 

Agriculturists  who  think  to  supply  the  place  of  manure  by 
frequent  and  deep  ploughing,  have  been  disappointed,  and 
their  fields  have  been  gradually  impoverished  by  crops,  until 
they  became  barren.  When  humus  is  put  on  a  clay  soil,  it  is 
retained  with  such  tenacity  by  the  clay,  that  the  free  contact 
of  air  is  prevented,  and  it  decomposes  more  slowly, — for  this 
reason  clay  requires  a  larger  quantity,  other  things  being 
equal,  to  produce  the  same  effects,  than  other  soils. 

Sand  allows  free  access  of  air  to  the  humus,  which  is  incor- 
porated with  it,  and  thereby  favors  its  decomposition  and 
consequent  fertilizing  power.  Lime  and  potash  destroy  the 
acidity  of  sour  humus,  and  favor  its  decomposition:  sour 

15 


170  SCIENTIFIC   AGRICULTURE. 

humus  contains  an  insoluble  extractive  matter,  which  is  inju- 
rious to  vegetation.  A  soil  which  abounds  in  sour  humus 
produces  little  but  reeds,  rushes,  flags,  sedge,  and  other  poor 
and  unpalatable  plants:  such  soils  are  rendered  fertile  by 
draining,  burning  and  alkalies, 


CHAPTER  III. 


PHYSICAL   PROPERTIES    OF    SOILS. 

THE  physical  properties  of  soils  necessary  to  be  considered 
are,  density,  weight,  state  of  division,  firmness  and  adhesive- 
ness, power  of  imbibing  moisture,  power  of  containing  water, 
power  of  retaining  water,  capillary  power,  contractibility  on 
drying,  power  of  absorbing  gaseous  matters,  power  of  absorb- 
ing heat,  power  of  containing  heat,  and  power  of  radiating 
heat. 

The  weight  of  a  soil  depends  upon  its  density,  or  the 
proximity  and  density  of  its  particles.  Dense  soils  retain  heat 
longer  than  light  ones,  and  afford  a  firmer  support  to  the  roots 
of  plants. 

The  following  table,  from  Johnston,  shows  the  relative 
weight  of  several  soils. 

A  cubic  foot  of  dry  silicious  or  calcareous  sand  weighs  180  Ibs. 

"         "     Half  sand  and  half  clay  "  95 

"         "     Of  common  arable  land  "  80  to  90 

"         "     Of  pure  agricultural  clay  "  75 

"         "     Of  rich  garden  mold  "  70 

"         "     Of  a  peaty  soil  "39  to  50 

The  state  of  division  of  the  particles  composing  the  soil  has 

an  effectvupon  its  weight,  as  well  as  money  value.      A  soil 

eomposecTof  clay,  sand,  coarse  and  fine  gravel  and  vegetable 


172  SCIENTIFIC    AGRICULTURE. 

mold,  is  superior  in  all  respects  to  to  one  composed  of  either  of 
these  ingredients  alone. 

Firmness  and  adhesiveness. — Most  soils  become  hard  and 
stiff  in  some  degree,  by  the  cohesion  of  their  particles  after 
being  thoroughly  wet.  Clay  soils  become  hard  and  difficult  to 
pulverize  when  thoroughly  dried,  while  pure  sand  soils  scarcely 
cohere  at  all.  This  varies  according  to  the  relative  amount  of 
sand  and  clay  or  lime  in  the  soil.  The  practical  inference  is, 
that  a  sandy  soil  is  improved  by  clay,  and  a  stiff  clay  soil  is 
ameliorated  by  sand. 

The  power  of  imbibing  moisture  is  possessed  by  all  fertile 
soils.  In  dry  weather,  this  quality  in  soils  is  highly  important, 
in  order  that  moisture  may  be  absorbed  from  the  dews  of  the 
night,  to  compensate  to  the  roots  of  plants  what  they  had  lost 
by  exhalations  from  their  leaves  and  evaporation  from  the  soil, 
during  the  day. 

During  a  night  of  twelve  hours,  when  the  air  is  moist, 
according  to  Schubler, 

1000  pounds  of  perfectly  dry  quartz  sand  will  gain      0  Ibs. 
"         "  Calcareous  "          "  2 

"         "  Loamy  soil  "          21 

"         "  Pure  agricultural  clay  "  27 

"         "  Rich  peaty  soils,  still  more. 

Power  of  containing  water,  in  dry  climates,  constitutes  one 
of  the  most  important  characteristics  of  arable  soils.  A  good 
soil  for  ploughing  or  tilling  must  be  capable  of  containing  from 
30  to  70  per  cent,  of  its  weight  of  water:  soils  which  allow 
their  moisture  to  sink  down  immediately  after  rains,  below  the 
reach  of  the  roots  of  plants,  are  valuable  only  "  for  pine  plan- 
tations or  laying  down  to  grass." — [Johnston.] 

The  following  table  from  Schubler  shows  the  relative  capacity 
of  soils  for  containing  water.  By  this,  we  mean,  the  amount 
of  water  which  a  given  quantity  of  earth  will  imbibe  and 


SCIENTIFIC   AGRICULTURE.  173 

contain,  before  it  is  saturated  or  full,  so  as  to  allow  the  water 
to  drop  or  run  out 

From  106  Ibs.  of  dry  soil,  the  water  will  begin  to  drop,  if  it 
be  a  quartz  sand,  when  it  has  absorbed  25  Ibs. 

Calcareous  sand,  "     "     "         "  29 

Loamy  soil,  «     "     "         "  40 

English  chalk,  «     "     «         «  45 

Clay  loam,  «     «     "         «  50 

Pure  clay,  "     «     "         «  70 

Power  of  retaining  water. — Evaporation  is  constantly  going 
on  from  the  surface  of  the  earth,  except  when  the  atmosphere 
is  saturated,  or  rain  or  dew  is  falling.  The  rapidity  with  which 
soils  become  dry  after  rains,  depends  upon  the  tenacity  with 
which  chey  retain  water :  as  a  general  rule,  those  soils  which 
are  capable  of  containing  the  most  water,  also  retain  it  with 
the  greatest  tenacity.  Thus  a  sand  soil  will  lose  as  much 
water  in  one  hour  as  a  clay  in  three,  or  peat  soil  in  four  hours. 
On  this  property  depends  in  a  great  degree  the  warmth  or 
coldness  of  a  soil. 

The  capillary  power  of  the  soil  is  exhibited  by  pouring 
water  into  the  bottom  of  a  flower  pot,  when  it  will  be  seen 
that  the  earth  gradually  takes  up  the  water,  and  the  moisture 
soon  appears  on  the  surface.  In  the  same  way  the  surface 
soil  absorbs  moisture  from  the  subsoil ;  and  when  this  contains 
an  excess  of  water,  the  surface  is  also  too  wet  and  cold.  Open, 
porous  soils,  -such  as  sand,  peat  and  humus,  possess  greater 
capillary  power  than  stiff  clay.  Upon  this  action  the  soil  is 
dependent  for  its  supply  of  moisture  during  dry  weather: 
upon  this,  also,  the  roots  of  plants  are  dependent  for  a  supply 
of  soluble  saline  matters,  which,  during  rains,  have  been 
washed  down  into  the  subsoil  beyond  their  reach.  This  is  the 
principal  means  by  which,  in  hot,  dry  climates,  where  rains 
seldom  or  never  fall,  the  soil  obtains  sufficient  moisture  to 
produce  vegetation.  This  capillary  action  explains  the  exis- 

*15 


174  .  SCIENTIFIC    AGRICULTURE. 

tence  of  the  thick  crusts  of  nitrate,  carbonate  and  chloride  of 
soda,  which  are  met  with  in  Peru  and  other  parts  of  South 
America,  India  and  Egypt  These  salts  are  brought  to  the 
surface  by  capillary  action,  in  a  state  of  solution,  and  deposited 
as  the  water  evaporates. 

Contractibility  on  drying. — Some  soils  contract  or  shrink 
on  becoming  dried  after  rains,  much  more  than  others;  and 
this  appears  to  be  in  proportion  to  their  power  of  retaining 
•water.  Thus  clay  and  peat  diminish  in  bulk  one  fifth  on  being 
perfectly  dried  after  saturation,  while  sand  maintains  the  same 
bulk  in  either  state. — [Johnston.]  This  contraction  in  clay 
soils  has  a  tendency  to  tear  and  injure  the  small  and  tender 
roots  of  plants. 

Power  of  absorbing  gaseous  matters.— rThe  necessity  of  free 
access  of  air  to  the  soil  has  already  been  noticed;  and  in 
proportion  to  the  amount  of  air  which  is  admitted  into  the  soil, 
will  be  the  oxygen  and  other  gases  absorbed  and  made  avail- 
able to  the  roots  of  vegetation.  Clays,  peat  and  humus  absorb 
more  oxygen  than  sandy  soils ;  this  is  due  partly  to  difference 
in  porosity,  and  partly  to  the  chemical  character  of  each.  Be- 
sides oxygen,  soils  absorb  carbonic  acid,  ammonia,  nitric  acid, 
and  other  vapors  which  contribute  to  fertility.  All  soils  absorb 
gaseous  substances  the  most  readily  when  in  a  moist  state ;  so 
that  dews  and  showers  are  of  great  benefit,  in  bringing  the  soil 
into  a  condition  to  extract  from  the  air  fresh  supplies  of  the 
gases. 

Power  of  absorbing  heat. — The  earth  is  capable  of  absorbing 
lieat  during  sunshine,  so  as  to  attain  a  temperature  above  the 
surrounding  air.  Dark  colored,  brown  and  reddish  soils  absorb 
heat  most  rapidly,  and  become  warm  the  soonest  They  also 
become  from  three  to  eight  degrees  warmer  than  other  colored 
soils,  and  by  this  means  they  promote  the  growth  of  vegetation 
better  than  those  of  other  colors.  This  property  gives  an 
additional  value  to  dark  soils  over  light  ones,  in  countries 


SCIENTIFIC    AGRICULTURE.  17-"> 

where  sunshine  is  deficient,  and  in  fields  which  bavo  a  northern 
aspect 

Power  of  retaining  heat. — As  heat  always  tends  to  seek  an 
equilibrium,  it  follows  that  after  the  sun  has  disappeared,  and 
his  rays  cease  to  shine  on  a  particular  part  of  the  earth,  the 
amount  of  heat  which  it  has  absorbed  above  that  of  the  air  is 
gradually  given  off  again  to  the  latter,  until  their  temperature 
is  equal,  or  until  the  air  becomes  the  coldest, — as  in  frosty 
nights.  A  peat  soil  cools  more  quickly  than  clay,  and  clay 
more  quickly  than  sand.  This  difference  must  have  an  influ- 
ence on  the  growth  of  crops.  In  cold,  wet  soils,  the  property 
of  radiating  heat  slowly  compensates  in  some  degree  for  the 
injury  done  (o  plants  by  these  conditions.  It  also  prevents  the 
formation  of  dew  and  frost,  as  soon  as  would  otherwise  be  the 
case.  On  the  contrary,  soils  which  radiate  heat  faster  promote 
the  formation  of  dew  by  becoming  cooled  below  the  dew  point 
sooner,  and  in  this  way  compensate  in  some  small  degree,  for 
deficiency  of  rain. 

The  absorbing,  as  well  as  radiating  power  of  the  soil,  may 
be  increased  by  a  top  dressing  of  soot,  charcoal,  muck,  or  some 
dark  colored  manure.  The  principle  of  absorption  and  radia- 
tion as  dependent  upon  color,  holds  true  in  relation  to  plants, 
as  well  as  to  soils:  and,  if  all  other  conditions  are  favorable, 
the  light  colored,  (white  straw,)  crops  should  be  cultivated  on 
dark  colored  soils,  and  the  dark  colored,  (green  straw,)  crops 
on  the  light  colored  soils* 

The  study  of  the  mechanical  and  physical  properties  of 
soils  is  of  more  importance  than  has  generally  been  supposed. 
These  have  now  been  discussed  as  fully  as  limits  would  admit, 
and  we  conclude  the  subject  by  stating  finally,  what  are  the 
ultimate  uses  and  relations  of  the  soil  to  plants. 

*  This  idea  is  original  with  the  author,  so  far  as  he  knows :  whether 
of  any  value  or  not,  others  may  judge  and  decide. 


176  SCIENTIFIC    AGRICULTURE. 

First,  the  soil  serves  as  the  foundation  for  upholding  and 
giving  mechanical  support  to  the  vegetable  structure. 

Secondly,  it  absorbs  light,  heat,  air  and  moisture,  which  are 
indispensable  to  healthy  vegetation. 

Thirdly,  it  supplies  both  the  organic  and  inorganic  elements 
required  by  the  plant  as  food. 

Fourthly,  it  is  a  chemical  laboratory,  in  which  these  ele- 
ments are  constantly  being  prepared  to  be  taken  into  the  plant 
by  its  roots. 


CHAPTER  IV. 


TILLAGE. 

ALL  operations  upon  the  soil  for  its  improvement  and  prepa- 
ration for  crops,  may  be  included  under  the  two  heads  of 
tillage  and  stercology,  or  manuring.  Tillage  includes  the 
operations  of  draining,  irrigation,  paring  and  burning,  rotation 
of  crops,  fallow,  extirpation  of  weeds  and  insects,  ploughing, 
ribbing,  lapping,  laying  in  beds,  scarifying  or  grubbing,  subsoil 
ploughing,  trenching,  rolling,  harrowing,  hoeing,  spading,  &c. 

The  objects  of  tillage  are, — 1.  To  loosen  the  soil  and  render 
it  permeable  to  air,  water  and  the  roots  of  plants.  2.  To  bring 
up  the  subsoil  and  mix  it  with  the  surface.  3.  To  incorpo- 
rate manures  with  the  soil.  4.  To  allow  free  access  of  the 
heat  and  light  of  the  sun.  5.  To  pulverize  the  coarse  and 
compact  portions.  6.  To  destroy  weeds  and  insects.  V.  To 
bury  green  crops  designed  for  manures.  8.  To  render  wet 
soils  dry  and  arable.  .9.  To  supply  a  sufficiency  of  water  to 
dry  soils.  10.  Tojix  movcable  and  light  blowing  soils.  11.  To 
clear  the  soil  of  roots  ami  stones.  12.  To  cover  seeds  with 
soil  "after  sowing.  t  -.  .5^%*$**"— ^. 

The  following  operations  are  described  by  Colman,  and  are, 
part  of  them,  peculiar  to  the  agriculture  of  Europe. 

Lapping  consists  in  turning  a  furrow  upon  an  unploughed 
surface,  so  that  when  the  field  is  finished,  it  is  only  half 
ploughed. 


178  SCIENTIFIC    AGRICULTURE. 

Ribbing  resembles  lapping,  except  that  two  furrows,  instead 
of  one/  are  turned  upon  the  same  unploughed  space. 

Stitching  or  laying  in  beds  consists  in  turning  two  furrows* 
back  to  back,  and  then  ploughing  alternately  on  either  side, 
until  the  bed  is  from  5  to  60  feet  wide,  and  leaving  deep  fur- 
rows between  all  the  beds. 

Trench  ploughing  consists  in  making  a  deep  furrow,  by 
ploughing  one  furrow  directly  in  another. 

Subsoil  ploughing  consists  in  breaking  up  and  loosening  the 
subsoil  with  a  plow  for  that  purpose,  and  without  inverting  the 
surface. 

Scarifying  or  grubbing  differs  from  harrowing  only  by  being 
performed  with  a  cultivator  or  similar  instrument,  which  goes 
deeper  into  the  earth  than  the  common  harrow,  for  the  purpose 
of  pulverizing  the  soil,  and  bringing  up  roots  and  stones  to  the 
surface. 

The  other  operations  of  tillage  need  not  be  described,  as 
they  are  common  and  well  understood.  There  can  be  no 
question  that  much  of  the  success  of  productive  agriculture 
depends  upon  the  perfection  of  tillage.  A  perfect  tillage 
requires  the  combination  of  patient  labor,  mechanical  imple- 
ments of  the  best  construction,  and  skill  in  the  operations. 

A  poor  soil  well  tilled  may  produce  better  crops  than  a  good 
soil  without  tillage.  Thorough  tillage,  by  mixing  and  pulveri- 
zing the  soil  sufficiently,  is  a  means  of  saving  manures  and 
greatly  increasing  the  return  of  the  harvest:  it  is  not,  however, 
true,  as  once  supposed,  that  tillage  will  supercede  the  neces- 
sity of  all  manures ;  it  only  compensates  for  part  of  the  manure 
requisite,  and  facilitates  the  operation  of  that  which  is  applied. 
The  Chinese,  and  some  nations  of  Europe,  have,  by  a  perfect 
svstem  of  tillage,  rendered  barren  soils  fertile,  and  caused 
fertile  soils  to  vield  harvests  of  almost  incredible  amount. 


flCIENTIFIC   AGRICULTURE.  179 

IRRIGATION. 

Irrigation  has  been  practiced  by  the  Chinese  and  Egyptians 
from  the  remotest  antiquity.  In  countries  where  rains  seldom 
fall,  and  the  ground  becomes  dry  and  parched,  irrigation  is  of 
immense  value.  It  consists  in  taking  water  from  lakes,  sewers, 
running  streams  or  reservoirs,  and  causing  it  to  flow  over  the 
land  by  means  of  small  canals  or  furrows,  then  by  proper  out- 
lets to  carry  it  off  again.  It  is  confined,  according  to  Colman 
and  Johnston,  almost  exclusively  to  meadow  lands. 

The  benefits  of  irrigation  in  a  country  where  rain  falls  fre- 
quently and  abundantly,  are  the  same  as  those  of  manuring. 
When  the  water  used  holds  in  suspension  any  organic  matters, 
they  subside  while  the  water  remains  on  the  fields,  and  leave 
a  visible  layer  of  manure  on  the  surface,  after  the  water  is 
drained  off.  An  example  of  the  fertilizing  effects  of  irrigation 
is  seen  in  the  lands  along  the  banks  of  the  Nile  and  Ganges. 
But  the  effects  of  irrigation  with  water  that  contains  no  organic 
sediments,  must  be  considered  the  same  as  that  of  rains.  Run- 
ning water  furnishes  to  plants  some  gasses,  which  are  absorb- 
ed, and  in  this  way  are  beneficial.  Crops  of  young  and  ten- 
der plants  should  be  irrigated  by  pure  water :  it  may  be  re- 
peated every  two  or  three  weeks  when  there  is  any  want  of 
rain,  and  the  water  be  allowed  to  lie  on  the  field  only  three  or 
four  days.  It  is  thought  by  English  Agriculturists  to  be  inju- 
rious to  meadows  to  flood  them  immediately  after  mowing. 

Warping  is  a  process  similar  to  irrigation:  the  object  of 
this,  however,  is  more  especially  to  obtain  the  sediments  of 
muddy  streams,  &c. ;  the  water  should  never  be  allowed  in 
either  process  to  remain  on  the  field  until  stagnated.  Irriga- 
tion is  most  beneficial  on  land  which  is  well  drained  beneath, 
so  as  to  allow  the  water  to  penetrate  the  subsoil,  and  not  stand 
too  long  on  the  surface.  Meadow  lands  are  sometimes  water" 
ed  in  the  winter  to  prevent  the  injurious  effects  of  frost  upon 
the  roots  of  the  grass.  Irrigation  is  not  practiced  to  much  ex- 


180 


SCIENTIFIC    AGRICULTURE, 


tent  in  the  United  States;  and  the  remoteness  of  many  farms 
from  streams,  as  well  as  the  expense  attending  the  operation, 
will  prevent  its  universal  application,  even  where  it  would  be 
beneficial. 

PARING    AND    BURNING.* 

Paring  and  Burning  is  much  practiced  in  many  parts  of 
Europe,  particularly  in  Great  Britain;  but,  so  far  as  we  are 
informed,  it  is  but  little  practiced  in  the  United  States.  It  is 
done  mostly  upon  sward,  peat  and  turf  soils.  The  operation 
consists  in  removing,  with  a  plow  or  spade,  a  slice  from  the 
surface,  from  one-  to  three  inches  thick  :  this  is  piled  up  in 
small  heaps  along  with  other  combustible  matters,  such  as 
brush,  weeds  and  decayed  wood ;  these,  when  sufficiently  dry, 
are  fired  and  allowed  to  smoulder  and  burn  slowly  until  the 
whole  is  reduced  to  ashes.  The  ashes  are  then  spread  evenly 
over  the  surface  of  the  soil.  The  quantity  of  ashes  which  is 
sometimes  obtained  in  this  way  at  a  single  burning,  is  stated 
by  Colman  to  be  2660  bushels,  or  about  77  tons  per  acre. 

The  benefits  of  paring  and  burning  are, — 1.  It  disentegrates 
and  reduces  to  fineness,  some  stones  and  hard  clay.  2.  It  de- 
stroys insects,  with  their  eggs  and  larvae.  3.  It  reduces  vege- 
table matter  to  ashes  and  gases,  which  are  available  for  the 
immediate  food  of  a  crop  of  plants.  There  are  some  objec- 
tions to  this  process,  which  ought  to  be  stated,  as  it  involves 
some  principles  not  wholly  understood. 

One  objection  is  that  it  consumes  too  much  of  the  vegeta- 
ble and  organic  matters  of  the  soil:  another  is  the  amount  of 
labor  required  in  the  operation.  The  benefit  however,  of  par- 
ing and  burning  upon  cold,  moist,  sour,  peat  and  turf  soils,  is 
unquestionable.  The  lime  and  potash  produced,  serve  to  neu- 
tralize acids  in  the  soil,  and  the  iron,  if  it  contain  any,  is  brought 
to  a  higher  degree  of  oxydation. 

On  light,  sandy,  gravelly  soils,  where  vegetation  is  thin  and 

*  This  operation  is  very  little  practiced  in  America. 


SCIENTIFIC   AGRICULTURE.  181 

there  is  little  organic  matter  present,  this  practice  is  injurious. 
The  process  of  burning,  according  to  Boussingault,  ought  to 
cease  after  the  organic  matters  are  reduced  to  a  blackish  ash ; 
for  when  carried  beyond  this,  so  that  incineration  is  complete 
and  a  red  ash  is  left,  it  may  materially  injure,  if  not  render 
the  soil  barren. 

DRAINING. 

The  draining  of  wet  lands  has  become  one  of  the  most  im- 
portant branches  of  mechanical  agriculture.  An  excess  of 
water  in  the  soil  prevents  the  access  of  air,  reduces  the  tem- 
perature, favors  the  formation  of  frost,  fogs  and  mildew,  and 
renders  tillage  difficult  or  impossible.  Soils  may  be  rendered 
too  wet  in  various  ways,  as,  by  the  tides  of  the  sea,  by  the 
setting  back  of  rivers,  by  permanent  springs  in  the  soil,  by 
small  subterranean  streams,  and  by  the  compact  and  retentive 
nature  of  the  soil  or  subsoil.  The  advantages  of  draining,  and 
the  various  modes  by  which  it  is  best  accomplished,  are  well 
described  by  Johnston  and  Colman,  from  whose  works  the  fol- 
lowing facts  in  relation  to  the  operation  are  derived. 

1.  It  carries  off  all  stagnant  water,  and  gives  a  ready  escape 
to  the  excess  of  what  falls  in  rain.  2.  It  prevents  the  ascent 
of  water  from  below,  either  by  capillary  attraction,  or  springs. 
3.  It  allows  the  water  of  rains  to  penetrate,  and  find  a  ready 
passage  from  the  soil,  instead  of  washing  the  surface.  4.  The 
descent  of  water  through  the  soil  is  followed  by  fresh  air,  which 
occupies  the  space  just  left  by  the  water.  5.  The  soil  after 
thorough  draining  becomes  looser,  more  friable  and  easily 
broken  ;  this  is  especially  true  of  stubborn  clays,  which  in 
practice  become  altogether  another  soil.  6.  By  freeing  the 
soil  from  the  excess  of  water,  it  becomes  warmer,  and  thereby 
advances  the  crop  to  an  earlier  harvest:  thus  it  is  "equivalent 
to  a  change  of  climate"  7.  When  the  autumn  is  wet,  drain- 
ing carries  off  the  superabundance  of  water,  and  prepares  the 
land  for  sowing  fall  crops,  which  would  otherwise  be  retarded, 

16 


182  SCIENTIFIC    AGRICULTURE. 

or  altogether  prevented.  8.  In  its  consequences  it  is  equiva- 
lent to  an  actual  deepening  of  the  soil.  0.  In  wet  soils,  bone?, 
wood-ashes,  rape  dust,  nitrate  of  soda,  and  other  artificial  ma- 
nures are  almost  thrown  away.  10.  He  who  drains  confers  a 
benefit  upon  his  neighbors  also.  11.  It  produces  a  more  salu- 
brious climate,  and  conduces  greatly  to  the  health  and  moral 
happiness  of  the  whole  population. 

Several  different  modes  of  draining  are  practiced  in  Great 
Britain,  which  are  worthy  of  notice — some  of  them  arc  also 
known  and  practiced  in  the  United  States.  The,  process  of 
draining  by  open  ditches  is  the  rudest,  and  was  doubtless  the 
first  form  of  draining.  Covered  drains  were  next  substituted, 
of  various  construction.  One  form  of  these  is  made  by  dig- 
ging a  ditch,  and  then  filling  it  with  straw  or  faggots,  and  cov- 
ering it  over  with  the  earth  which  was  thrown  out.  Another 
form  is  excavated  so  as  to  taper  to  a  point  at  the  bottom,  and 
having  a  shoulder  left  at  the  height  from  the  bottom  which  it 
is  desirable  to  cover  the  waier-course.  This  is  then  covered 
by  an  inverted  sod,  which  rests  on  the  shoulders;  after  which 
the  earth  thrown  out  in  excavating  is  returned,  and  the  surface 
levelled.  Another  process  is  by  the  mole  plow  :  another  by 
filling  the  bottom  of  a  ditch  with  small  stones  of  uniform  size. 
Two  other  forms,  called  in  England  tile  and  pipe  drains,  are 
constructed  by  means  of  tile  and  pipes  made  of  brick  clay, 
and  are  said  to  form  water-courses  which  are  both  cheap  and 
durable. 

FALLOWING. 

"By  fallowing,  it  has  been  known  in  all  ages  that  the  produce 
of  the  land  was  capable  of  being  increased.  How  is  this  in- 
crease to  be  accounted  for  t  We  speak  of  leaving  the  land  to 
rest,  but  it  can  really  never  become  wearied  of  bearing  crops. 
It  cannot,  through  fatigue,  lie  in  need  of  repose.  In  what,  then, 
does  the  efficacy  of  naked  fallowing  consist?"  (Johnston.) 

Some  agriculturists  reject  the  practice  of  fallowing  as  use- 


SCIENTIFIC   AGRICULTURE.  188 

less,  upon  the  supposition  that  all  the  objects  accomplished  by 
it,  may  be  also  by  the  application  of  manures.  The  proposal 
to  substitute  manures,  is  of  course  equivalent  to  an  admission 
that  fallow  is  beneficial  to  the  soil.  Now  if  any  change  takes 
place  in  the  soil  while  lying  in  fallow,  we  must  first  know  what 
that  change  is  before  we  can  determine  whether  manures  will 
affect  the  same  change :  and  in  order  to  know  this,  we  must 
have  an  exact  analysis  of  the  soil,  before  the  fallowing  begins, 
and  at  the  end  of  its  term ;  this  will  show  what  new  elements 
are  formed,  and  what  old  ones  are  decomposed. 

If,  tlven,  we  have  a  manure  which  will  furnish  to  the  soil  all 
the  elements  which  were  formed  by  chemical  action  during  fal- 
low ing,  it  will  fulfil  the  same  indication.  But  in  either  case, 
an  analysis  of  the  soil  is  requisite  before  the  fact  can  be  estab- 
lished :  and  inasmuch  as  those  who  discard  fallowing,  have 
made  no  such  analysis,  they  have  made  no  demonstration  of 
the  truth  of  their  position.  And  until  farther  facts  are  de- 
veloped by  chemical  experiment,  it  may  be  fairly  questioned, 
whether,  on  all  soils,  and  under  all  circumstances,  fallow  can  be 
dispensed  with.  The  benefits  to  be  derived  from  allowing  land 
to  lie  in  naked  fallow  are  enumerated  by  Johnston  as  follows : 

1.  In  strong  clay  soils,  fallow  affords  opportunity  for  destroy- 
ing weeds,  which  it  is  difficult  to  extirpate  while  the  land  is 
continually  bearing  crops.  2.  The  weeds  and  herbage  which 
spring  up  during  summer,  afford  an  abundant  crop  for  green 
manure  :  they  should  be  ploughed  under  before  their  seeds 
ripen.  3.  Land  which  is  continually  cropped,  becomes  ex- 
hausted of  certain  elements  within  the  depth  to  which  their 
roots  extend.  By  leaving  the  soil  at  rest,  the  rains  which  fall 
and  circulate  through  it,  equalize  the  distribution  of  the  solu- 
ble substances  which  it  contains.  The  water  which  in  dry 
weather,  ascends  by  capillary  attraction  from  below,  brings  up 
Baline  compounds  and  deposits  them  as  it  evaporates.  4.  Some 
subsoils  require  to  be  turned  up  and  exposed  to  the  action  of 


184  SCIENTIFIC  AGRICULTURE. 

the  air  for  some  time,  before  they  can  be  safely  mixed  with 
the  surface  soil.  5.  The  soil  often  contains  more  or  less 
organic  matter  which  is  inert,  or  decays  so  slowly  as  to  be 
almost  unavailable  to  vegetation :  by  leaving  this  to  decompose 
and  become  fitted  for  the  food  of  plants,  the  crop  which  fol- 
lows will  grow  more  luxuriantly  and  yield  more  abundantly. 
6.  The  nitrates,  which  are  very  favorable  to  vegetable  growth, 
are  more  rapidly  formed  when  the  land  lies  in  naked  fallow 
than  when  covered  with  crops.  7.  The  fragments  of  rocks  of 
various  kinds  are  disintegrated  and  decomposed  faster  during 
fallow  than  during  cropping.  8.  The  saline  and  other  sub- 
stances, such  as  ammonia,  magnesia,  the  nitrates,  &c.,  which 
are  brought  down  by  rains,  accumulate  in  the  soil  during  fal- 
low. 9.  The  clay,  oxide  of  iron,  and  organic  matter  of  the 
soil,  have  the  power  of  extracting  ammonia  from  the  air;  and 
this  is  the  more  rapid,  the  greater  the  extent  of  surface  which 
is  uncovered  and  exposed  to  the  passing  air.  10.  The  light 
soils  sometimes  become  too  loose  to  afford  sufficient  mechani- 
cal support  to  the  roots  of  crops,  and  require  time  to  settle 
together  and  resume  their  cohesion  and  compactness. 

No  doubt  the  period  usually  allowed  to  land  to  lie  in  fallow 
may  in  many  cases  be  very  much  abridged,  and  in  some  cases 
altogether  dispensed  with.  Whenever  follow  is  beneficial,  it 
must  be  ascribed  to  some  one  or  more,  if  not  all  the  above 
causes  combined. 

ROTATION    OF    CROPS. 

By  rotation  of  crops,  is  implied,  the  alternate  production  of 
different  plants  in  regular  succession  on  the  same  land.  Expe- 
rience has  shown  that  the  same  crop  cannot  be  produced 
successively  on  the  same  field  for  an  indefinite  period  of  time. 

The  grasses  and  forest  trees  seem  to  present  an  exception 
to  this  principle :  but  it  must  be  observed  that  the  grasses  are 
mowed  or  pastured  down  before  arriving  at  maturity, — for,  if 
they  were  allowed  to  perfect  their  growth  and  ripen  their 


SCIENTIFIC  AGRICULTURE.  185 

seeds,  tho  same  result  would  follow  as  in  other  crops.  And 
with  regard  to  forest  trees,  it  has  been  observed  that  where  an 
oak  forest  has  been  cut  down,  a  growth  of  pine  will  succeed; 
and  where  a  pine  forest  has  been  cleared  away,  a  growth  of 
oak  will  spring  up  in  its  place :  where  beech  and  maple  are 
cut,  poplar  and  basswood  often  succeed  them.  Thus  it  appears 
that  the  soft  and  hard  woods  alternate  with  each  other. 

The  reasun  formerly  given  for  the  necessity  of  rotation  was, 
that  all  plants  throw  off  certain  matters  or  excrements  by  their 
roots,  which  prove  injurious  to  another  crop  of  the  same  kind 
of  plants  j  but  which  are  beneficial  rather  than  injurious  to 
crops  of  a  different  kind. 

This  beautiful  theory  originated  with  the  distinguished  bota- 
nist, Decandolle,  and  explains,  apparently,  in  an  easy  and  satis- 
factory manner,  all  the  reasons  for  the  necessity  of  rotation 
of  crops.  The  simplicity  and  high  authority  of  this  theory 
obtained  for  it,  for  many  years,  an  unquestioned  assent;  and 
the  only  objection  which  lies  against  it  now  is,  that  it  is  not 
supported  by  a. single  fact 

The  objections  to  it  are, — 1.  That  plants  do  not  excrete  so 
great  an  amount  of  noxious  matters  as  supposed  by  Decan- 
dolle. 2.  No  evidence  exists  of  their  injurious  effects  upon 
the  plants  from  which  they  are  excreted.  3.  There  has  been 
no  demonstration  of  their  nutritive  effects  on  other  plants. 

This  theory,  then,  must  be  abandoned,  and  we  must  look 
for  one  which  is  supported  by  facts:  and  if  one  cause  be  found 
adequate  to  explain  all  the  effects  produced,  we  are  not  bound 
to  seek  for  another. 

The  necessity  of  rotation  does  not  depend  upon  there  being 
too  much,  but  too  little,  of  some  particular  elements  in  the 
soil.  (Johnston.)  All  plants  require  certain  elements  for  food, 
and  these  are  indispensible  to  their  growth  and  maturity :  one 
plant  requires  them  in  certain  proportions  and  another  requires 
these  and  others  besides,  in  quite  different  proportions. 

*16 


186  SCIENTIFIC    AGRICULTURE. 

"If  we  assume,  [says  Petzholdt,]  that  the  utility  of  the  rota- 
tion of  crops  depends  exclusively  upon  the  circumstance  that 
all  cultivated  plants  withdraw  from  the  soil  unequal  amounts 
of  certain  ingredients  for  their  nutrition,  all  the  observed  facts 
are  at  once  satisfactorily  explained,  and  the  possibility  of  deter- 
mining the  rotation  of  crops,  or  of  avoiding  it  altogether,  if 
desirable,  made  evident." 

It  is  useless  to  remark,  that  no  plant  can  vegetate  in  a  soil 
which  does  not  contain  all  the  elements  which  it  requires  for 
its  food.  Some  species  of  grass  contain,  and  therefore  require 
for  their  growth,  a  large  amount  of  silica :  a  soil  which  contains 
no  silica  cannot  produce  them.  A  soil  may  contain  just  enough 
silica  for  one  crop,  but  not  enough  for  a  second,  so  that  a  second 
could  not  be  produced;  but  a  crop  of  some  other  plant  requiring 
much  less  silica,  might  be  grown  upon  it  as  successfully  as  the 
grass  before. 

"  A  single  crop  of  wheat  may  deprive  the  soil  so  completely 
of  one  of  its  mineral  constituents,  that  another  crop  of  wheat 
could  not  grow  upon  it;  and  yet  this  soil  may  contain  abundant 
mineral  constituents  for  the  production  of  a  good  crop  of  clover 
or  turnips."  An  analysis  of  a  soil  and  the  ashes  of  plants 
desired  to  be  produced  upon  it,  will  determine  negatively, 
whether  it  is  eligible  to  their  growth:  but  the  only  positive 
proof  is  a  trial  of  the  crop  upon  the  soil. 

All  plants  draw  certain  mineral  elements  from  the  soil,  but 
do  not  all  equally  exhaust  its  fertility.  All  knowledge  respect- 
ing the  application  of  manures,  and  the  adaptation  of  certain 
plants  to  particular  soils,  is  based  upon  these  facts.  The 
necessity  for  rotation  may  sometimes  be  obviated  by  allowing 
the  land  to  lie  in  fallow  for  a  year,  after  which  the  crop 
may  be  successfully  repeated.  Manuring  may  also  sometimes 
answer  the  same  purpose;  but  as  a  general  rule  in  practice, 
however  it  may  be  explained  in  theory,  a  judicious  rotation  is 
beneficial. 


SCIENTIFIC    AGRICULTURE.  18 

Boussinganlt  states  that  ho  saw  in  South  America,  fields  on 
which  good  crops  of  wheat  were  said  to  have  been  produced 
annually  for  more  than  two  centuries ;  and  also  that  potatoes 
arc  cultivated  continually  on  the  same  soil.  It  is  stated  also 
by  Colman,  that  onions  yield  more  and  more  abundantly  the 
oftener  they  are  grown  on  the  same  field.  These  statements 
either  contain  some  hidden  fallacy,  or  they  prove  that  the  fields 
in  question  contained  an  inexhaustible  amount  of  the  elements 
necessary  to  the  plants  produced ;  for  they  do  not,  nor  were 
they  designed  to  prove,  that  rotation  is  unnecessary. 

It  is  unquestionable  that  a  perfect  system  of  agriculture, 
and  the  maximum  production  of  all  crops,  requires  a  system 
of  alternation,  regulated  according  to  circumstances,  and  in 
accordance  with  the  principles  of  Chemistry.  A  valuable  end 
to  be  obtained  by  rotation  is  the  destruction  of  certain  weeds 
and  the  insects  which  inhabit  them. 

The  following  table  shows  a  system  of  rotation  which  is 
practiced  in  Pennsylvania. 

First  year — Grass  or  clover. 

Second  "     Pasture. 

Third      "      Indian  corn. 

Fourth   "      Oats  or  barley — (manured.) 

Fifth      «      Wheat. 

Sixth      "      Grass— (plastered.) 

The  tables  below  are  from  Colman,  and  show  some  courses 
of  rotation  practiced  in  England. 
First  year — Turnips — (manured.) 
Second  "      Barley. 
Third     "      Clover. 
Fourth  «     Wheat. 

0)i  a  Clay  Soil. 

First  year — Swedes  turnips  and  Mangel  Wurtzel. 
Second  "      Wheat  and  beans,  (i.  e.,  part  of  land  in  each.) 


188  SCIENTIFIC    AGRICULTURE. 

Oil  a  Clay  Soil — continued. 
Third  year — Clover. 
Fourth  "      Wheat  and  oats. 
Fifth       "      Vetches,  rye  and  turnips. 
Sixth      «     Wheat. 

On  a  Sandy  Soil. 

First  year — Swedes  and  Mangel  Wurtzel. 
Second  "      Barley. 
Third     "      Clover. 
Fourth  "      Oats. 

Fifth       "      Cabbage  and  potatoes. 
Sixth      "     Wheat. 

On  a  Limestone  Soil. 
First  year — Rye  and  turnips. 
Second  "      Barley. 
Third     "      Clover. 
Fourth    «      Oats. 
Fifth       "      Turnips. 
Sixth      "      Wheat 

The  table  below  is  from  Mr.  J.  J.  Thomas'  Prize  Essay :  it 
gives  three  courses,  which  are  said  to  be  well  adapted  to  the 
State  of  New  York. 

First  Course. 

First  year — Corn  and  roots,  well  manured. 
Second  "      Wheat  sown  with  15  Ibs.  clover  seed  per  acre. 
Third     "      Clover  one  or  more  years,  according  to  fertility 
and  amount  of  manure  at  hand. 

Second  Course. 

First  year — Corn  and  roots  with  manure. 
Second  "      Barley  and  Peas. 
Third     "     Wheat,  sown  with  clover. 
Fourth   "      Clover,  one  or  more  years. 


SCIENTIFIC    AGRICULTURE.  189 

Third  Course. 

First  year — Corn  and  roots,  with  manure. 

Second   "     Barley. 

Third      "     Wheat,  sown  with  clover. 

Fourth   "     Pasture. 

Fifth       "     Meadow. 

Sixth       "     Fallow. 

Seventh "     Wheat. 

Eighth    "      Oats  sown  with  clover. 

Ninth      "     Pasture  or  meadow. 

It  will  be  evident,  on  a  little  reflection,  that  no  definite  rules 
can  be  given,  and  no  set  of  tables  devised  which  shall  apply  to 
all  soils  and  under  all  circumstances.  The  frequency  of  any 
crop  in  the  course  of  rotation,  must,  therefore,  be  determined 
by  a  consideration  of  the  character  of  the  soil  and  subsoil,  the 
amount  of  manure  applied,  and  the  other  crops  which  come 
in  the  course.* 


*  "  In  wheat  farming  districts  and  with  the  wheat  farmer,  who  depends 
for  his  sales  and  profits  solely  upon  wheat  and  wool,  the  following  rota- 
tion with  slight  variation,  is  often  adopted. 

Divide  all  the  available  land  into  three,  six  or  nine  enclosures:  let 
one-third  be  always  in  wheat,  one-third  in  pasture  and  meadow,  and 
one-third  in  summer  crops  well  manured, — which  may  be  followed  with 
wheat  the  same  fall,  or  may  be  put  in  barley  the  next  spring,  and  fol- 
lowed with  wheat  and  well  clovered  in  all  cases.  The  general  practice 
is,  to  summer  fallow  the  clover  after  spring  pasturing.  There  should 
be  about  one  sheep  to  the  acre  of  all  the  available  land ;  the  manner  of 
cropping  the  fallow  is  important. 

Others  make  a  four  years'  rotation,  letting  the  clover  lay  two  years, — 
one  for  pasture  and  one  for  meadow.  On  this  system  no  more  ealtle 
should  be  kept,  or  butter  and  cheese  made,  or  corn,  oats  or  potatoes 
grown,  than  is  required  for  the  farm  use;  everything  is  made  subser- 
vient to  the  wheat  crop." — L.  B.  Langworthy. 


CHAPTER  V. 

STERCOLOGY.*  MANURES. 

ALL  agents  used  by  the  Agriculturist  to  preserve  or  restore 
the  productiveness  of  the  soil,  are  properly  called  manures. 
All  soils,  after  being  long  cultivated  and  subjected  to  the  ex- 
hausting- influence  of  continual  harvests,  become  deficient  in 
mineral  and  organic  elements,  which  must  be  replaced  artifi- 
cially or  total  barrenness  will  ensue.  Manuring  is  the  process 
by  which  this  end  is  accomplished, — and  for  it,  there  is  no 
substitute. 

If  the  supply  be  less  than  the  crops  require,  the  soil  increases 
in  barrenness :  if  it  just  replaces  what  lias  been  removed  by 
the  crops,  the  fertility  remains  the  same:  if  more  be  added 
than  the  crops  require,  the  fertility  of  the  land  is  increased. 

*A  NKW  TERM — STERCOLOGY, — Mr.  Editor:  I  wish  to  propose, 
through  your  paper  a  new  term,  which  I  think  will  supply  a  deficiency 
in  agricultural  language.  We  have  no  generic  term  which  embraces  in 
its  signification,  the  science  or  art  of  enriching  the  soil.  1  therefore 
propose  the  term  STERCOLOGY,  which  is  compounded  from  the  word 
stercus,  which  means  manure,  and  logos,  a  discourse. 

Although  hardly  general  enough  in  its  strict  meaning,  this  word  may, 
by  a  little  extension,  be  understood  to  embrace  everything  under  the 
head  of  manuring,  enriching,  ameliorating  or  amending  the  soil.  And 
although  words  are  only  the  signs  of  ideas,  and  technical  language 
should  not  be  used  unnecessarily, — still  a  systematic  division  of  any 
branch  of  science  into  parts  embraced  under  generic  heads  is  always 
convenient. 

Yours,  respectfully, 

M.  M.  RODGERS." 

Genesee  Farmer,  August,  1847. 


SCIENTIFIC    AGRICULTURE.  191 

The  remains  of  plants,  together  with  the  excrements  and  car- 
m  of  animals,  if  returned  to  the  soil  before  decomposition, 
must  contain  all  the  mineral,  organic  and  gaseous  elements,, 
which  the  plants  derived  from  the  soil  or  the  atmosphere. 
These  must  pass  through  the  different  processes  of  decompo- 
sition, before  they  assume  their  original  gaseous  and  earthy 
forms,  and  become  again  available  for  the  food  of  plants. 

The  whole  science  of  manuring  consists  in  supplying  to  the 
soil,  those  indispensible  elements  which  have  become  exhaust- 
ed. The  richest  manure  may  be  applied  to  a  failing  soil,  and 
if  it  lacks  a  particular  element  which  the  crops  require,  and 
which  the  soil  does  not  contain,  the  soil  grows  barren  notwith- 
standing the  manuring.  Farm-yard  manure,  probably  contains 
the  greatest  number  of  elements  necessary  to  fertility ;  but  par- 
ticular plants  require  special  manures. 

Manures  operate  beneficially  on  the  soil  in  several  ways. 

1.  By  serving  directly  in  some  instances  as  the  food  of  plants. 

2.  By  causing  chemical  changes  in  the  soil,  by  which  other 
substances  are  prepared  to  be  taken  up  as  nutriment  by  their 
roots.     3.  By  neutralizing  noxious  substances  in  the  soil  which 
prevent  the  growth  of  vegetation.     The  operation  of  lime  on  a 
cold,  sour,  peat  soil,  or  one  which  abounds  in  sulphate  of  iron, 
is  an  example  of  this  principle.     4.  Manures  change,  accord- 
ing to  their  bulk  and  texture,  the  mechanical  properties  of 
soils,     5.  They  may  change  more  or  less,  according  to  their 
various  properties,  the  physico  chemical  character  of  a  soil,  in 
relation  to  light,  heat,  air  and  water.     Sand,  used  upon  a  clay 
soil,  for  the  purpose  of  rendering  it  more  loose  and  friable, 
would  be  as  properly  a  manure,  as  farm  yard,  or  any  other 
variety.     Clay  used  to  ameliorate  a  sandy  soil,  is  also  in  effect 
a  manure. 

Manures  have  been  classified  in  various  ways,  according  to 
their  supposed  operation  and  nature.  The  most  simple  and 
convenient  division,  and  one  which  is  usually  adopted  at  pre- 


192  SCIENTIFIC    AGRICULTURE. 

sent,  is  that  which  arranges  all  of  them  into  three  classes,  viz: 
animal,  vegetable  and  mineral  manures.  The  first  class  includes 
all  substances  of  animal  origin :  the  second  includes  all  those 
of  vegetable  origin;  and  the  third,  all  those  derived  directly 
from  the  mineral  kingdom. 

O 

ANIMAL    MANURES.* 

Animal  substances  are  better  fertilizers  than  those  of  veget- 
able origin,  on  account  of  their  chemical  constitution  and  the 
facility  with  which  they  decompose :  they  furnish  more  manure 
in  proportion  to  their  bulk,  and  act  more  promptly  and  rapidly. 
The  properties  and  value  of  these  substances  are  given  mostly 
on  the  authority  of  Johnston  and  Boussingault. 

The  flesh  of  animals,  after  and  during  its  decomposition,  is  a 
rich  and  active  manure:  the  lean  flesh  acts  more  energetically 
than  the/a£. 

Blood  is  similar  in  its  properties  to  lean  flesh  ;  it  is  sometimes 
applied  as  a  top  dressing  in  the  form  of  dried  powder,  and 
sometimes  mixed  with  other  matters,  to  form  composts.  The 
scraps  of  skin  among1  the  refuse  of  curriers'  shops  are  also 
used  as  manure. 

Wool,  hair,  horns  and  hoofs  found  in  large  quantities  among 
the  refuse  of  various  manufactories,  contain  large  proportions 
of  carbon  and  nitrogen,  as  do  most  animal  substances,  and  are 
therefore  highly  concentrated  manures.  The  refuse  of  fisheries, 
soap  and  candle  factories,  slaughter  houses,  kitchens,  sugar 
manufactories,  &c.,  all  contain  matters  rich  in  those  elements 
which  characterize  good  fertilizers. 

Animal  charcoal,  which  is  to  be  obtained  in  considerable 
quantities  at  sugar  refiners'  shops,  in  a  state  of  mixture  with 
blood  and  lime,  is  a  manure  of  considerable  value. 

Bones  are  valuable  on  account  of  both  the  organic  an.d 
mineral  matters  which  they  contain,  The  bones  of  different 

*  See  tables  at  the  end  of  the  chapter. 


SCIENTIFIC    AGRICULTURE.  193 

animals  differ  somewhat  in  composition:  phosphate  of  lime 
constitutes  the  largest  proportion  of  the  matter  of  dry  bones ; 
the  amount  is  from  forty  to  sixty  per  cent  of  their  weight 
Eight  pounds  of  bone  dust  are  equal  in  phosphates  to  1000 
pounds  of  hay  or  wheat  straw. 

The  value  of  bones  is  not  dependent  alone  on  the  phos- 
phates, but  partly  upon  the  gelatine  and  other  organic  matters 
which  enter  into  their  composition :  these  latter  operate  in  the 
same  way  as  the  other  organic  tissues  of  animals.  Bones  are 
prepared  for  manure  by  boiling,  by  maceration  in  sulphuric 
acid  and  water,  and  by  grinding;  the  last  of  which  methods  is 
thought  on  all  accounts  to  be  preferable.  In  soils  deficient  in 
phosphates,  bones  are  of  great  value ;  and  from  the  compara- 
tively small  quantity  of  phosphates  which  most  crops  require, 
the  effect  of  a  large  manuring  with  bone  dust  is  manifest  upon 
the  land  for.  many  years:  "  260  pounds  of  bone  dust,  (less  than 
six  bushels,)  are  sufficient  to  supply  all  the  phosphates  con- 
tained in  the  crops  which  are  reaped  from  an  acre  during  an 
entire  fourshift  rotation  of  turnips,  barley,  clover  and  wheat 
Some  lands  remember  a  single  dressing  for  fifteen  or  twenty 
years.'*  (Johnston.) 

The  prolonged  effect  of  bones  is  due  to  the  organic  as  well 
as  mineral  matters.  Bones  should  not  be  ground  too  fine: 
they  are  particularly  applicable  to  turnip  crops  and  pasture 
lands :  the  milk  of  cows  contains  about  half  a  pound  of  phos- 
phates to  every  ten  gallons ;  hence  the  necessity  of  these  salts 
in  the  soil  of  pastures.  Animal  tissues,  when  used  as  manures, 
ought  to  be  well  covered  with  earth,  or  ploughed  under,  in 
order  to  facilitate  their  decomposition,  and  at  the  same  time 
prevent  the  escape  of  the  gases  formed  during  this  process. 

Solid  excrements  of  animals, — Night  soil,  or  human  ordure, 
is  a  highly  valuable  fertilizer.  It  is  best  prepared  for  use  by 
mixture  with  powdered  charcoal,  half  burnt  peat,  or  scil  which 
is  rich  in  vegetable  matter :  quick  lime  has  been  used  for  the 


194  SCIENTIFIC   AGRICULTURE. 

same  purpose ;  but,  although  it  destroys  the  odor,  it  dissipates 
at  the  same  time  a  large  portion  of  its  ammonia.  During  the 
decomposition  of  night  soil,  an  evolution  of  carbonic  acid, 
ammonia,  sulphuretted  and  phosphuretted  hydrogen  takes 
place.  After  the  escape  of  these  gases,  the  odor  ceases,  and 
the  remainder,  when  dried,  constitutes  what  is  sold  in  large 
cities  under  the  name  of  poudrette.  The  odor  of  recent  night 
soil  may  be  destroyed,  and  the  volatile  elements  retained,  by 
adding  to  it  gypsum  or  dilute  sulphuric  acid.  This  manure  is 
used  in  the  form  of  compost,  and  as  a  top  dressing  in  the  form 
of  poudrette. 

The  excrements  of  horned  cattle  are  more  valuable  and 
enduring  in  their  operation  than  those  of  the  horse  and  sheep. 
It  ferments  more  slowly  on  account  of  its  smaller  quantity  of 
nitrogen;  hence  it  retains  its  virtue  longer,  and  produces  a 
more  lasting  effect  on  the  soil.  It  is  colder  in  its  nature  than 
that  of  the  horse,  which  is  owing  partly  to  the  amount  of  water 
it  contains,  and  partly  to  its  peculiar  constitution. 

The  excrements  of  the  horse  abound  more  in  nitrogen  com- 
pounds than  those  of  cattle.  Even  where  both  are  fed  upon 
the  same  food,  those  of  the  horse  are  more  valuable  than  those 
of  the  cow.  It  begins  to  heat  and  ferment  in  a  short  time,  and 
in  two  or  three  weeks,  according  to  Johnston,  loses  nearly  half 
its  original  weight.  On  account  of  this  rapid  fermentation  and 
the  consequent  loss  of  volatile  matters,  it  should  be  mixed  as 
soon  as  possible  with  charcoal,  peat,  sawdust,  or  earth  rich  in 
vegetable  matters,  or  be  sprinkled  with  gypsum  or  dilute 
sulphuric  acid.  For  the  same  reason,  this  kind  of  manure 
ought,  contrary  to  popular  opinion,  to  be  spread  upon  and 
ploughed  into  the  soil  before  any  signs  of  fermentation  take 
place ;  unless  it  is  mixed  with  some  other  matters  to  form  com- 
posts. Erom  its  tendency  to  ferment  and  develop  heat,  it  is 
.  admirably  adapted  to  enter  into  all  composts.  An  additional 


SCIENTIFIC    AGRICULTURE.  105 

quantity  of  water  prevents  too  rapid  fermentation  and  pre- 
serves the  virtues  of  this  manure  to  a  considerable  extent 

The  excrements  of  the  hog  are  said  to  be  a  rich  manure ;  but 
they  have  a  strong  and  unpleasant  odor,  and  often  impart  a 
rank  taste  to  the  crops  upon  which  they  are  used:  for  this 
reason  it  has  been  advised  not  to  use  them  on  crops,  particu- 
larly of  roots,  which  are  designed  for  food.  They  are  colder 
and  less  inclined  to  ferment  than  those  of  the  cow,  and  should 
be  combined  with  other  manures  or  made  into  composts. 

The  excrements  of  sheep  form  a  richer  and  more  fermentable 
manure  than  those  of  the  cow :  they  are  said  to  be  most  bene- 
ficial on  soils  which  contain  much  vegetable  matter,  which 
absorbs  the  volatile  matters  which  would  otherwise  pass  off 
during  fermentation. 

The  value  of  all  animal  manures  depends  much  upon  cir- 
cumstances, viz :  the  food  upon  which  the  animal  is  fed ;  the 
age  and  condition  of  the  animal ;  the  amount  of  labor  he  per- 
forms; the  length  of  time  and  manner  in  which  the  manure  is 
kept  Since,  then,  their  value  is  affected  by  so  many  condi- 
tions, it  is  evident  that  no  general  conclusions  can  be  drawn, 
which  shall  not  be  liable  to  exceptions;  and  no  set  of  analyses 
can  furnish  tables  which  shall  in  all  eases  agree.  The  following 
tables  may  be  relied  upon  as  being  as  nearly  correct  as  can  be 
obtained,  and  sufficiently  so  for  all  practical  purposes. 

Excrements  of  birds. — These  are  among  the  most  powerful 
fertilizers.  The  excrement  of  pigeons  is  said  to  be  particularly 
valuable  to  flax  crops,  for  which  it  is  held  in  high  esteem  in 
some  parts  of  Europe.  This,  like  most  other  manures,  loses 
much  of  its  value  by  being  allowed  to  ferment  without  the 
admixture  of  some  other  matters  to  retain  its  volatile  elements. 
The  principal  value  of  this,  as  well  as  the  excrements  of  all 
birds,  which  have  been  analyzed  and  used  as  manures,  is 
dependent  mainly  on  the  large  proportions  of  ammonia  and 
phosphates  which  they  contain.  The  excrements  of  hens, 


196  SCIENTIFIC    AGRICULTURE. 

geeso,  turkeys  and  ducks,  are  of  less  value  than  those  of  the 
pigeon. 

Guano  is  the  excrements  of  sea  fowls,  and  is  an  earthy  sub- 
stance of  a  grayish  brown  color:  it  is  mostly  found  in  Africa 
and  South  America.  It  is  found  on  the  islands  and  coasts  of 
those  countries,  in  latitudes  where  the  weather  is  so  dry  that 
decomposition  has  proceeded  slowly,  and  it  has  consequently 
accumulated  in  large  quantities.  Guano  is  said  to  be  efficacious 
as  a  manure,  applied  to  almost  any  crop :  it  is,  however,  accord- 
ing to  Johnston,  more  advantageous  to  root  crops  than  to  grain 
or  grass  crops.  It  is  conveniently  applied  as  a  top  dressing, 
mixed  with  gypsum,  wood  ashes  or  powdered  charcoal.  Two 
or  three  hundred  pounds  to  an  acre  is  sufficient  for  a  single 
dressing. 

The  urine  of  men  and  animals  is  the  most  valuable  and  the 
most  neglected  of  all  manures.  That  of  the  cow  and  hog  is 
said  to  be  more  valuable,  because  it  contains  more  solid  soluble 
matter  than  that  of  any  other  domestic  animal.  The  efficacy 
of  urine  as  a  manure  is  due  to  the  large  quantity  of  urea, 
ammonia  and  phosphates,  and  consequently  of  nitrogen,  which 
it  contains.  Recent  urine  generally  exerts  an  unfavorable 
influence  on  growing  vegetation ;  it  is  most  beneficially  applied 
after  fermentation  has  fairly  commenced,  and  before  it  reaches 
the  final  stage  of  the  process.  (Johnston.) 

Decomposition  is  attended  with  a  diminution  of  urea,  and  an 
increase  of  ammonia.  It  is  important  that  the  urine  collected 
should  be  fermented  in  tightly  covered  cisterns  to  prevent  the 
escape  of  volatile  matters :  it  has  been  proposed  to  add  gyp- 
sura,  sulphate  of  iron,  or  sulphuric  acid,  to  the  fermenting 
urine,  in  order  to  fix  the  ammonia;  the  mixture  of  vegetable 
mold  with  it  has  been  also  recommended  as  equally  effective 
and  more  economical.  The  loss  of  manure  in  waste  urine  in 
densely  populated  countries  and  large  cities,  is  immense,  as  is 
shown  by  the  following  calculation. 


SCIENTIFIC  AGRICULTURE.  197 

[If  we  allow  the  quantity  of  urine  voided  by  each  indvidual  to  be 
COO  pounds  yearly,  the  city  of  Rochester,  which  contains  30,000  inhabi- 
tants, would  furnish  yearly  1,200,000  pounds,  or  540  tons.  This,  esti- 
mated at  the  price  of  guano  would  be  worth  $21,600.  Now  if  we  esti- 
mate the  number  of  horses  and  cows  of  the  city  to  500  of  each,  and 
that  each  animal  voids  as  much  urine  as  two  persons,  the  amount  would 
be  80,000  pounds,  or  40  tons,  which  would  be  worth  $1,600.  Here 
then  is  a  loss,  if  we  reckon  guano  at  $40  per  ton  of  $23,200:  or  of 
manure  enough  to  produce,  in  addition  to  the  ordinary  crop,  over 
16,000  bushels  of  wheat  in  a  single  year.  These  calculations  may  not 
be  correct,  but  they  approximate  this  point  sufficiently  for  our  purpose.] 

VEGETABLE    MANURES. 

Organic  vegetable  matters  in  various  conditions,  constitute 
the  largest  part  of  manure  in  use.  The  form  in  which  they 
are  prepared  and  applied  has  an  important  influence  on  their 
fertilizing  effect.  The  principal  difference  between  dry  and 
green  vegetable  matter  is,  that  the  latter  decomposes  more 
rapidly  and  therefore  acts  more  promptly.  Unripe  plants  fur- 
nish a  more  valuable  manure  than  ripe  ones. 

Straw  and  chaff,  when  ploughed  into  the  soil  dry,  are  slow 
in  decomposing,  and  act  more  slowly  than  when  previously 
fermented.  The  question  of  applying  straw  without  previous 
decomposition,  is,  in  practice,  only  a  question  of  time.  It  is 
doubtless  true  that  it  furnishes  about  the  same  amount  of 
manure  in  both  cases  ;  but  in  the  one  case  it  has  a  more 
speedy  and  powerful,  and  in  the  other  a  more  prolonged  effect 

Saw  dust,  is  a  cheap,  and  on  some  accounts  a  valuable  ma- 
nure :  it  ferments  slowly  in  the  soil,  and  cannot,  therefore,  be 
much  relied  upon  the  first  year  or  two.  It  is  beneficial  in  ab- 
sorbing gases  and  liquid  manures,  and  its  effect  is  felt  gradually 
by  the  soil  as  decomposition  proceeds : .  it  is  also  beneficial  to 
stiff  clay  land  by  rendering  it  more  loose  and  light 

Dry  leaves  and  decayed  wood,  operate  as  manures  in  a  man- 
ner similar  to  saw  dust ;   they  are  however  better  fitted  by 
decomposition  in  compost  heaps. 
*17 


198  SCIENTIFIC    AGRICULTURE. 

Oil  calces,  from  cotton  and  linseed  exhausted  of  their  oils, 
are  valuable  as  fertilizers ;  but  their  value  for  fattening  animals 
perhaps  exceeds  that  as  a  manure,  and  may  prevent  their 
direct  use  for  this  purpose. 

Peat,  is  used  with  benefit  on  soils  which  are  deficient  in 
organic  matters  :  it  decomposes  slowly,  especially  if  sour  or 
applied  alone  to  a  wet  soil  containing  little  lime.  Its  action, 
when  properly  decomposed  and  prepared,  is  the  same  as  that 
of  other  vegetable  matters  :  it  usually  contains  more  or  less 
mineral  and  gaseous  matters,  which  have  their  own  peculiar 
operation ;  but  these  are  not  to  be  considered  as  affecting  the 
vegetable  character  of  peat  as  a  manure.  On  account  of  the 
slowness  with  which  it  decays,  it  should  be  mixed  with  lime, 
gypsum,  wood  ashes,  or  some  vegetable  matter  which  decom- 
poses rapidly,  such  as  farm-yard  manure  :  swamp  muck  and 
humus  are  similar  in  properties  to  peat. 

Tanners'  bark,  is  used  as  a  manure,  but  is  liable  to  the 
same  objection  as  peat 'in  respect  to  its  slow  decay:  it  is  bes^ 
brought  into  a  state  of  fermentation  by  mixture  with  lime  and 
farm-yard  manure  in  composts. 

Soot,  is  a  complicated  substance,  as  will  be  seen  by  refer- 
ence to  the  table :  it  contains  many  things  necessary  to  vegeta- 
tion, and  is  a  manure  of  some  value ;  but  experiment  has  not 
yet  determined  its  precise  character  and  operation. 

Charcoal,  on  account  of  its  power  of  absorbing  gases  and 
destroying  offensive  odors,  is  a  valuable  addition  to  the  soil : 
its  operation  is  not  so  direct  as  that  of  some  other  manures; 
that  is,  it  is  not  so  useful  on  account  of  any  element  which  it 
furnishes  to  plants,  as  by  the  intermediate  office  which  it  per- 
forms of  absorbing  and  retaining  in  the  soil  those  volatile  mat- 
ters which  plants  require,  and  which  would  otherwise  escape 
and  be  lost.  It  is  beneficial  as  a  top  dressing,  and  as  an  in- 
gredient in  composts :  it  evolves  carbonic  acid  in  its  decompo- 
sition, and  is  in  this  way  directly  useful  to  plants.  Its  power- 


SCIENTIFIC  AGRICULTURE.  199 

ful  antiseptic  properties  render  it  very  beneficial  to  young  and 
tender  plants  ;  by  keeping  the  soil  free  of  putrefying  sub- 
stances which  would  otherwise  destroy  their  spongiolos  and 
prevent  their  growth. 

Farm-yard  manure.  The  manner  and  state  in  which  farm- 
yard manure  should  be  applied,  has  been  a  subject  of  much 
experiment  and  controversy.  The  conclusions  of  Johnston  ia 
relation  to  this  subject,  appear  rational  and  satisfactory.  This 
kind  of  manure  is  made  up  of  the  solid  and  liquid  excrements 
of  animals  together  with  straw  and  hay,  some  of  which  are  in 
a  state  of  decomposition,  and  the  remainder  fresh  and  un- 
changed. The  question  as  to  which  condition  these  manures 
should  be  used  in,  must  depend  upon  circumstances.  If  the 
object  is  to  furnish  the  greatest  amount  of  organic  matter  to 
the  soil,  the  sooner  the  manure  is  applied  after  it  is  made,  the 
better  this  object  is  accomplished.  On  compact  clays,  the 
mixture  of  straw  and  coarse  manure  is  beneficial,  as  it  renders 
them  looser  and  lighter,  while  the  products  of  decomposition 
are  more  completely  retained  in  the  soil  than  they  would  be  in 
a  loose  one.  But  coarse  manures  render  loose  soils  more  loose, 
and  lose  more  of  their  elements  in  decomposing  :  for  these 
reasons,  compact  fermented  manures  are  preferable  in  such 
soils.  For  manuring  crops  which  grow  rapidly  and  attain 
maturity  in  a  short  time,  well  fermented  manures  and  fine 
composts  are  felt  more  immediately  and  powerfully  than  re- 
cent ones.  Such  crops  as  turnips,  buckwheat,  clover,  and 
many  garden  vegetables,  might  nearly  attain  maturity  before 
decomposition  would  be  sufficiently  advanced  in  new  and  coarse 
manures  to  render  them  beneficial.  When  it  is  desired  to  force 
and  quicken  the  growth  of  a  crop,  a  well  fermented,  or  fine 
heating  manure  should  be  used;  such  as  rich  compost,  bone 
dust,  or  the  excrements  of  the  horse  and  sheep. 

Top  dressing  for  pastures,  meadows  and  turnip  crops,  should 
usually  be  of  the  same  kind  as  these  just  named.  But  farm. 


200  SCIENTIFIC    AGRICULTURE. 

yard  manure  is  not  subject  to  any  special  law,  but  is  to  be  used 
according*  to  its  quality  and  condition,  and  adapted  to  circum- 
stances. Vegetable  substances  are  all  similar  in  their  nature 
and  operation,  and  are  modified  by  conditions  and  circum- 
stances. They  are  all  subject  to  the  same  laws,  and  their 
relative  value  depends  on  their  constitution  and  adaptation  to 
each  particular  case. 

GREEN    MANURES. 

By  green  manures,  is  understood  those  plants  which  are 
grown  for  the  purpose  of  being  ploughed  in  and  mixed  with  the 
soil  before  being  harvested  or  used  as  food  for  animals.  This 
plan  of  manuring  is  by  no  means  of  recent  origin  ;  it  was 
known  and  practiced  among  the  Romans.  The  plants  most  in 
•use  for  this  purpose  in  the  United  States  are  red  clover,  buck- 
wheat and  grass  in  the  form  of  green  sward.  Several  other 
plants  are  used  in  Europe,  viz.,  rape,  lupine,  vetches,  rye,  tur- 
nip, carrot  and  beet  tops,  borage,  spurry,  sea  weeds  and  fresh 
water  plants. 

The  advantages  of  green  manures,  according  to  Johnston, 
are, — 1.  They  undergo  decomposition  sooner  than  dry  vegeta- 
ble matter,  and  consequently  become  sooner  available  for  the 
food  of  succeeding  crops.  2.  The  nitrogen  and  carbon  which 
they  contain,  if  allowed  to  decay  in  the  open  air,  are  lost  ; 
while  if  the  plants  had  been  buried,  before  decay,  these  gases 
would  have  been  mostly  retained  in  the  soil  for  the  use  of  suc- 
ceeding crops.  3.  By  ploughing  in  a  crop  of  plants,  the  or- 
ganic matter  is  more  equally  distributed  through  the  soil  than 
could  be  done  by  any  other  means.  4.  Green  manures  are 
available  where  other  manures  are  scarce,  and  in  soils  deficient 
in  organic  matter.  5.  The  plants  used  as  green  manures,  bring- 
up  towards  the  surface  by  their  roots,  matters  which  had  sunk 
into  the  soil  too  deep  to  be  of  much  service.  6.  It  restores  to 
the  soil  all  it  took  from  it,  in  a  more  soluble  and  available  con- 


SCIENTIFIC    AGRICULTURE.  201 

dilion ;  and  in  addition  to  this,  those  gases  also  which  the  plants 
extracted  from  the  air  during  growth.  7.  A  green  crop  yields 
more  manure  than  the  same  crop  could  do  in  any  other  form. 
8.  A  grain  crop  is  greater  on  the  same  field  when  green,  than 
when  fermented  manures  are  used.  The  best  plants  for 
green  manures  are  those  which  grow  the  fastest,  produce  the 
most  vegetable  matter,  and  with  the  smallest  expense. 

Sufficient  seed  should  be  sown,  that  the  plants  may  coyer 
the  ground  completely;  the  crop  should  be  ploughed  in  before 
the  time  of  full  blowing,  because  the  flowers  give  off  nitrogen, 
which  is  wasted  in  the  air.  Agriculturists  agree  that  a  seconJ 
and  third  crop  of  green  plants  still  continue  to  improve  the 
soil;  but  there  must  be  a  limit,  beyond  which  this  practice 
cannot  be  carried  with  benefit  and  profit  Green  manuring 
might  perhaps  secure  a  field  against  barrenness  for  an  indefi- 
nite period  of  time,  providing  nothing  was  ta!*en  off:  but  if  a 
crop  was  occasionally  carried  away,  in  must  of  course  be  im- 
poverished to  the  amount  of  what  is  taken  off  in  mineral 
matters.  It  is  probably  true  that  lands  in  a  state  of  nature, 
which  are  covered  with  forest  trees  or  other  vegetation,  never 
become  barren. 

The  soil  may  in  time  become  deficient  in  a  particular  mineral 
element  which  the  incumbent  plants  require ;  but  when  these 
die  out,  others  immediately  spring  up  by  a  natural  rotation, 
and,  requiring  elements  slightly  different  from  the  first,  grow 
as  luxuriantly  as  they  did.  Thus  one  race  of  plants  succeeds 
another,  each  in  turn  exhausting  the  soil  of  certain  elements, 
and  leaving  it  richer  in  others.  The  question  may  arise,  What 
becomes  of  the  mineral  elements, which  are  lost,  if  nothing  is 
taken  off  the  soil,  since  they  do  not  escape  into  the  air?  The 
probability  is,  they  sink  down  deeper  and  deeper  into  the  soil 
in  the  form  of  soluble  salts,  until  beyond  the  resell  of  the 
roots  of  plants. 


202  SCIENTIFIC    AGRICULTURE. 

IMPROVEMENT    OF    THE    SOIL    BY    PASTURE. 

Pasture  may  be  either  temporary  or  permanent  Tempo- 
rary pasture  consists  in  laying  down  a  field  to  pasture  for  one, 
two  or  three  years,  or  more.  The  soil  is  benefitted  by  pasture 
in  several  different  ways.  The  roots  of  the  grass  which  remain 
furnish  a  large  amount  of  organic  matter,  which,  to  a  soil  poor 
in  this  constituent,  is  of  great  benefit.  Land  which  lies  several 
years  will  be  more  benefitted  than  when  it  lies  but  a  single 
year;  but  the  first  year  enriches  it  more  than  any  succeeding 
one.  The  result  to  the  land  will  be  nearly  the  same,  whether 
the  grass  be  mown  or  eaten  off  by  the  stock,  "  That  farming 
is  the  most  economical,  where  the  land  will  admit  of  it,  which 
permits  the  clover  or  grass  to  occupy  the  land  for  a  single 
year  only." 

Permanent  pasture  consists  in  the  suspension  of  grain  crops, 
and  the  occupation  of  the  land  by  grass  or  clover,  for  an  indefi- 
nite period  of  time.  Besides  the  benefit  which  the  soil  derives 
from  the  organic  matters  left  in  it,  some  of  its  mineral  con- 
stituents are,  by  the  action  of  air,  moisture,  and  the  roots  of 
the  grass,  brought  into  a  more  soluble  state  to  be  used  by 
succeeding  crops.  Another  advantage  of  pasture,  especially 
on  stiff  clay  soil,  is  that  it  renders  it  more  loose  and  friable. 
On  dry,  sandy  soils,  pasture  is  beneficial,  by  retaining  the 
moisture  longer,  and  also  the  dry  organic  matters  and  fine 
sand  upon  the  surface,  which  would  otherwise  be  blown  away 
by  the  winds.  Insects  perform  a  part  in  improving  pasture 
lands,  which  is  by  no  means  insignificant. 

They  subsist  upon  the  organic  matters  of  the  soil,  which, 
they  bring  into  a  minute  state  of  division  and  deposit  on  the 
surface  as  they  ascend  by  night  through  their  holes.  They 
furnish  also,  considerable  organic  matter,  which  is  rich  in 
nitrogen,  by  the  death  and  decay  of  their  own  bodies.  Thus 
these  earth  worms  and  insects,  in  the  lapse  of  a  few  years, 
furnish  a  vast  amount  of  the  richest  manure  without  the 


SCIENTIFIC    AGRICULTURE.  203 

smallest  expense.  The  time  which  land  may  lay  in  pasture 
and  still  increase  in  richness,  must  have  a  limit, — and  this 
depends  upon  the  quality  of  the  soil  and  the  kinds  of  grass 
which  occupy  it. 

The  soil  will  require  an  occasional  top  dressing,  or  the  pas- 
ture will  deteriorate:  on  account  of  the  exhaustion  of  certain 
elements  in  the  soil,  grasses,  as  well  as  forest  trees  and  other 
plants,  tend  to  a  natural  rotation;  one  species,  after  flourishing 
a  few  years,  begins  to  decline  and  finally  dies  out,  and  is 
replaced  by  another,  and  this,  in  time  by  another, — and  so  on, 
indefinitely.  All  pasture  lands  whatever,  which  are  arable, 
can,  after  a  series  of  years,  be  subjected  to  grain  crops;  and 
this  in  most  cases  would  doubtless  be  expedient.  This  how- 
ever, must  be  determined  in  each  particular  case,  by  an  appre- 
ciation of  all  the  circumstances  and  conditions. 


CHAPTER  VI. 


MINERAL  MANURES. 

MINERAL  manures  are  divided,  for  the  sake  of  convenience? 
into  saline  and  earthy ;  the  former  including  pure  salts  whose 
composition  is  exactly  known,  such  as  common  salt  and  car- 
bonate of  soda ;  and  the  latter  including  the  various  earthy 
matters  used  to  ameliorate  the  soil,  such  as  lime,  wood  ashes, 
and  marl.  The  mineral  manures  are  all  supposed  to  have  a 
specific  mode  of  action,  which  is  "peculiar  to  each  respectively: 
the  theory  of  their  action,  however,  as  fertilizers,  cannot,  for 
want  of  space,  except  in  a  few  cases,  be  detailed.  But  few, 
comparatively,  of  the  known  mineral  fertilizers  are  in  common 
use,  and  those  only  will  be  described. 

SALINE    MANURES. 

Carbonate  of  soda. — This  salt,  according  to  Johnston,  is 
beneficial  on  lands  abounding  in  sulphate  of  iron,  or  overgrown 
with  mosses  and  other  noxious  vegetation ;  and  also  as  a  top 
dressing  to  fields  of  young  grain,  and  wherever  wood  ashes 
would  be  useful.  It  is  said  to  be  peculiarly  beneficial  to  the 
strawberry.  From  forty  to  sixty  pounds  may  be  applied  to 
an  acre,  either  in  powder  mixed  with  other  manure,  or  in 
solution. 

Sulphate  of  soda,  or  Glauber's  sail,  has  been  used  with 
much  benefit  on  fruit  trees,  rye,  beans,  beets,  and  some  other 
crops.  The  quantity  used  should  be  at  least  one  hundred 


SCIENTIFIC    AGRICULTURE.  203 

pounds  per  acre,  cither  in  solution  or  in  powder  just  before  a 
rain.  [It  must  not  be  inferred,  that  this,  or  any  other  manure, 
because  it  is  recommended  for  a  particular  species  of  plants,  is 
not  therefore  adapted  to  the  growth  of  others;  but  those  only 
are  mentioned,  upon  which  they  have  been  tried  sufficiently  to 
warrant  a  conclusion  as  to  their  efficacy.] 

Sulphate  of  magnesia,  or  epsom  salts,  is  said  to  be  useful  to 
young  crops  of  wheat,  clover,  peas  and  beans:  one  or  two 
hundred  pounds  to  an  acre  should  be  used. 

Sulphate  of  lime,  or  gypsum. — This  salt  of  lime,  usually 
called  "plaster,"  has  been  long  known  and  much  employed  as 
a  fertilizer  on  almost  all  crops  and  soils.  It  requires  much 
water  for  its  solution.  The  beneficial  operation  of  gypsum  is 
supposed  to  depend  upon  several  circumstances.  This,  like  all 
the  sulphates,  furnishes  sulphur,  which  is  important  in  the 
nutrition  of  plants,  especially  those  of  the  liguminous  order. 
Gypsum  prevents  the  escape  of  ammonia  which  is  deposited 
in  the  soil  by  rain,  and  evolved  by  the  decomposition  of  ani- 
mal and  vegetable  matters.  In  soils  deficient  in  lime,  it  supplies 
this  element  in  an  available  state  for  their  nutrition.  It  has 
been  thought  to  operate  most  beneficially  on  red  clover  and 
Indian  corn. 

Nitrate  of  soda  is  on  some  accounts  a  good  fertilizer;  it  has 
not  come  into  general  use,  and  is  not  as  well  understood  in  its 
relations  to  soils  and  to  plants  as  it  should  be.  Several  results 
are  theoretically  attributed  by  Johnston  to  the  action  of  the 
nitrates  on  vegetation.  1.  They  give  a  dark  green  color  to 
the  leaves.  2.  They  hasten  and  sometimes  prolong  the  growth 
of  vegetation.  3.  They  increase  both  the  straw  and  the  grain 
of  the  cereals.  4.  They  impart  a  saline  taste  to  hay  and 
straw,  which  causes  cattle  to  eat  them  with  more  avidity. 
5.  Grain  which  has  been  manured  with  the  nitrates  yields 
more  bran  and  less  flour  than  those  manured  with  other  salts 
The  nitrates  increase  the  oat  crop ;  they  should  not,  however, 

18 


206  SCIENTIFIC   AGRICULTURE. 

be  used  for  any  crop  on  land  which  is  already  disposed  to 
produce  too  much  straw.  They  are  exceedingly  soluble,  and 
are  for  this  reason  not  so  beneficial  on  loose,  light  soils,  because 
more  easily  washed  away  than  on  close,  compact  soils :  for  the 
same  reason  they  produce  little  effect  after  the  first  year. 
They  furnish  a  large  amount  of  nitrogen,  and  are  most  bene- 
ficial to  poor  soils  which  are  deficient  in  organic  matters. 

Chloride  of  sodium,  or  common  salt,  has  been  used  with 
yarious  results  as  a  fertilizer.  Plants  require  for  their  growth 
both  of  the  elements  of  common  salt,  viz, — chlorine  and  soda ; 
and  in  soils  which  are  deficient  in  one  or  both  of  these  ele- 
ments, there  can  be  no  doubt  as  to  its  efficacy ;  but  in  a  soil 
which  contains  them  in  sufficient  quantity  in  a  soluble  state,  it 
cannot  be  expected  that  this  salt  will  be  of  any  service.  It  is 
most  likely  to  prove  beneficial  on  lands  lying  remote  from  the 
sea,  and  which,  consequently,  would  be  more  apt  to  require  it. 
This  salt  is  of  more  benefit  to  green  crops  than  cereals;  and 
also  to  hasten  and  increase  the  growth  of  the  herbage  of  plants 
than  the  seeds. 

The  chlorides  of  lime  and  magnesia  contained  among  the 
refuse  of  chemical  manufactories,  are  also  used  as  manures 
with  good  effects.  The  chlorides  are  destructive  to  both  ani- 
mal and  vegetable  life,  when  used  in  large  quantity;  they 
have  consequently  been  used  to  destroy  weeds,  worms  and 
insects  in  the  soil. 

The  silicate  of  potash  and  soda,  and  the  various  salts  of 
ammonia,  are,  without  question,  powerful  fertilizers,  particu- 
larly on  the  grasses;  but  they  are  not  in  general  use,  on 
account  of  their  high  price,  as  well  as  doubtful  reputation 
among  those  practical  men  who  have  not  tested  them. 

EARTHY    MANURES. 

Wood  ashes.  The  ashes  of  wood  and  all  other  vegetable 
matter,  contain  various  proportions  of  several  different  salts,  all 
of  which  are  necessary  to  the  growth  of  plants.  The  following 


SCIENTIFIC    AGRICULTURE.  207 

table  presents  an  analysis  of  the  ashes  of  the  red  beech  and 
oak,  by  SprengeL 


Red  Beech. 

Oak. 

Silica, 

5.52 

26.95 

Alumina, 

2,33 

Oxide  of  Iron, 

3.77 

8.14 

Oxide  of  Manganese, 

3.65 

Lime, 

2o.OO 

17.38 

Magnesia, 

5.00 

1.44 

Potash, 

22.11 

16.20 

SooX 

3.32 

6.73 

Sulphuric  Acid, 

7.64 

3.36 

Phosphoric  Acid, 

5.62 

1.92 

Chlorine, 

1.84 

2.41 

Carbonic  Acid, 

14.00 

15.47 

100.  100. 

It  will  be  seen  by  the  table,  that  one  kind  of  ash  is  richer 
in  one  element,  and  another  in  some  other  element :  the  value 
of  each  must  be  estimated  accordingly.  The  ashes  of  the  oak 
and  beech,  both  contain  more  lime  than  they  do  potash,  and 
would  therefore  be  as  efficacious  on  a  soil  deficient  in  lime,  as 
on  one  deficient  in  potash.  We  see,  then,  that,  contrary  to 
popular  opinion,  the  ucility  of  this  manure  does  not  depend 
solely  upon  the  action  of  potash,  but  on  several  other  elements 
also. 

Ashes,  as  a  general  rule,  are  used  with  benefit  on  the 
grasses,  lugurninous  and  Indian  corn  crops.  They  may  be 
mixed  with  an  equal  quantity  of  gypsum  or  bone  dust,  and 
applied  to  the  amount  of  ten  to  thirty  bushels  to  an  acre;  or, 
if  the  ashes  have  been  leached,  fifty,  sixty,  or  a  hundred 
bushels  may  be  used  to  an  acre.  According  to  Johnston,  only 
about  one  fifteenth  part  of  the  weight  of  ashes  are  immediately 
soluble ;  their  effects  are  therefore  more  permanent  than  those 


208  SCIENTIFIC    AGRICULTURE. 

of  any  of  the  soluble  saline  manures,  being  felt  by  the  land  for 
more  than  ten  years. 

The  following  mixture  is  said  to  be  nearly  equal  in  efficacy 
for  a  year  or  two,  to  one  ton  of  wood  ashes. 

Crude  potash,  60  pounds. 

Grystalized  carbonate  of  soda,     60        " 

Sulphate  of  soda^  20 

Common  salt,  20       " 

160 

Leached  ashes  are  nearly  destitute  of  potash,  and  cannot,  of 
course,  supply  this  substance  to  vegetation;  they  are  said, 
however,  to  be  of  service  to  oat  crops  in  particular,  and  are 
beneficial  to  clay  soils.  The  ashes  of  coal,  peat,  turf,  straw 
and  cane  are  also  valuable  as  fertilizers,  according  to  their 
constitution  and  the  crops  to  which  they  are  applied. 

Crushed  or  pulverized  rocks  of  various  kinds  could  be  used 
with  the  same  benefit  and  in  the  same  cases,  according  to  their 
elementary  composition,  as  other  mineral  manures:  crushed 
granite  would  furnish  a  considerable  amount  of  potash ;  it  is 
easily  ground  after  being  heated  to  a  red  heat.  Crushed  trap 
contains  much  lime,  and  is  a  good  manure :  crushed  lavas  are 
also  valuable  on  most  soils. 

Marl.  The  composition  and  other  chemical  characters  of 
marl  have  been  described :  it  consists  of  lime,  clay,  and  often 
sand,  shells,  and  other  matters.  The  object  and  effect  of 
marling  are  similar  to  those  of  liming  land.  Marl  should  be 
used  according  to  its  constitution ;  clay  marl  should  usually  be 
put  on  sandy  soils,  and  lime  or  sandy  marl  on  clay  soils.  The 
best  time  for  laying  on  marl  is  at  the  end  of  autumn,  so  that 
it  may  be  pulverized  by  frosts  during  the  winter  Boussin- 
gault  says,  land  which  contains  ten  per  cent,  of  carbonate  of 
lime  can  dispense  with  marl. 

The  effect  of  marl  is  not  unlimited,  but,  like  lime,  requires 


SCIENTIFIC  AGRICULTURE.  209 

to  be  repeated  once  in  10  or  12  years.  With  regard  to  the 
quantity  of  marl  which  should  be  used  to  an  acre,  we  must  be 
governed  by  the  same  rational  considerations  as  the  use  of  all 
other  manures ;  viz.,  it  should  be  applied  where  it  is  required, 
and  in  quantity  equal  to  the  demand  of  the  soil.  The  opin- 
ions of  practical  men  vary  greatly  on  this  subject :  according 
to  Johnston,  ten  or  fifteen,  to  one  hundred  and  twenty  tons 
are  used  to  an  acre ;  while  Boussingault  says,  "  allowing  the 
broadest  margin,  and  judging  from  the  composition  of  the  ashes 
of  the  plants  of  ordinary  crops,  we  can  see  that  the  quantity 
of  three  and  a  half  bushels  of  marl  of  the  usual  composition 
per  acre,  which  is  assumed  as  the  average  quantity  to  be  laid 
on,  is  vastly  more  than  can  be  absolutely  necessary." 

This  discrepancy  has  arisen  partly  from  the  extravagant 
notions  about  the  virtues  of  marl,  and  partly  from  the  nature 
of  the  marl  and  the  soils  to  which  it  has  been  applied  by  dif- 
ferent experimenters. 

Chalk  is  much  used  as  a  fertilizer  in  some  parts  of  Europe 
where  it  is  cheap  and  abundant ;  but,  from  its  scarcity  and 
price,  it  can  never  be  expedient  to  use  it  in  this  country  while 
we  have  such  an  abundance  of  lime  in  various  other  forms. 
When  used,  it  is  subject  to  nearly  the  same  laws  as  lime  and 
marl.  Its  composition  varies  ;  some  specimens  contain  more 
phosphate  of  lime,  magnesia  and  silicates,  than  others.  Ehren- 
berg  has  made  the  remarkable  discovery,  that  chalk  to  a  con- 
siderable extent,  is  composed  of  the  shells  or  skeletons  of  ma- 
rine microscopic  animals. 

Lime.  The  chemical  and  physical  properties  of  lime  have 
already  been  described,  and  it  remains  for  us  to  examine  briefly 
the  principles  of  its  adaptation  to  the  soil  as  a  fertilizer.  Much 
discussion  has  been  had,  and  many  long  essays  written  on  this 
subject;  but  no  chemist  claims  for  this  substance  any  excep- 
tion to  general  chemical  laws,  or  attributes  to  it  any  action 
more  specific  than  that  of  any  other  manure.  There  is  no 

18* 


210  SCIENTIFIC    AGRICULTURE. 

doubt  that  all  our  present  knowledge  of  lime  as  a  manure, 
can  be  expressed  in  a  few  known  and  plain  principles:  we  do 
not  assume  that  all  is  known  about  lime  that  may  be  known  at 
some  future  time,  but  that  the  facts  can  be  much  more  briefly 
and  perhaps  more  clearly  set  forth  than  is  done  by  most  wri- 
ters on  agriculture. 

Lime  is  perhaps  the  most  important  mineral  used  as  a  ma- 
nure. When  applied  to  a  soil  entirely  destitute  of  lime,  the 
quantity  will  necessarily  be  larger  than  at  subsequent  periods. 

The  quantity  used  must  be  determined,  as  in  all  other  cases, 
by  circumstances.  No  general  rule  can  be  given  for  its  use, 
but  each  one  must  judge  from  the  facts  in  the  case  and  pro- 
ceed accordingly.  Johnston  says,  "if  we  suppose  one  per  cent 
to  be  necessary,  then  upwards  of  300  bushels  of  slaked  lime 
must  be  mixed  with  a  soil  six  inches  in  depth,  -to  impart  to  an 
acre  this  proportion."  On  wet,  peaty,  marshy,  or  clay  soils, 
more  lime  will  be  necessary  than  on  dry,  sandy  and  loose  soils : 
on  soils  which  contain  much  organic  matters  also,  more  may  be 
used  than  on  those  nearly  destitute  of  them.  It  is  consider- 
ed better  economy  to  apply  lime  in  smaller  quantities  and  at 
shorter  intervals,  than  to  use  it  in  large  quantities  at  more  dis- 
tant period?. 

Caustic  lime  should  be  applied  to  marshy  and  clay  soils  im- 
mediately after  slaking:  when  allowed  to  slake  in  the  open  air 
spontaneously,  without  the  use  of  water,  it  is  more  mild,  and 
better  adapted  to  grass  lands  and  young  crops;  but  W7hen  ap- 
plied to  naked  fallow  and  mixed  with  the  soil,  it  may  be  used 
in  either  state.  Burned  lime  is  well  adapted  to  the  compost 
form  of  manures.  As  quick  lime  dissipates  the  ammonia  of 
fermenting  manures  in  the  soil,  it  ought  not  to  be  applied  at 
the  same  time,  nor  to  come  in  immediate  contact  with  them : 
it  is  best  applied  usually  in  the  fall,  or  as  long  as  possible  be- 
fore the  next  crop  is  sown. 

These  principles  apply  only  to  caustic  lime :  unburned  lime, 


SCIENTIFIC    AGRICULTURE.  211 

marl,  gypsum,  chalk,  and  composts  containing  Urn?,  may  be 
applied  at  any  time.  Lime,  in  order  that  it  may  produce  its 
full  effect  and  most  lasting  benefit,  should  bo  kept  near  the 
surface.  This  may  be  done  by  sub-soil  ploughing,  by  which 
the  lime  is  thrown  up  to  the  surface;  and  also  by  sowing  deep 
rooted  crops,  which  will  reach  it  after  it  has  sunk  too  deep  to 
benefit  others  of  shorter  roots.  The  amount  of  lime  in  the 
soil  gradually  diminishes  from  several  causes,  when  it  is  not 
occasionally  replenished  :  it  is  removed  to  a  small  extent  with 
the  annual  harvests,  and  by  assuming  new  forms  by  chemical 
action  ;  a  portion  is  also  carried  away  in  solution  with  the 
water  which  falls  by  rain  and  filters  through  both  the  surface 
and  subsoil. 

The  beneficial  effects  of  lime,  although  more  permanent,  are 
not  felt  as  soon  as  those  of  some  other  mineral  manures :  it  is 
of  little  service  on  soils  deficient  in  organic  matter.  The  length 
of  time  which  lime  shows  its  effects  upon  the  crops  and  soil,  is, 
according  to  circumstances,  from  ten  to  thirty  years.  Its  use 
is  sometimes  attended  by  unfavorable  results  when  not  judi- 
ciously used:  light,  loose  soils  are  rendered  too  loose;  and  the 
growth  of  certain  noxious  weeds  favored  by  its-presence  :  an 
ov(r-doso  destroys  too  much  organic  matter,  hardens  certain 
soils,  ^id  injures  the  spongioles  of  young  plants.  It  is  said  to 
operate  injuriously  upon  flax,  by  causing  tenderness  of  its  cor- 
tical fibre. 

These  remarks  on  the  use  of  lime  as  a  manure,  are  conden- 
sed from  Johnston,  who  has  given  perhaps  the  best  treatise  on 
lime  extant.     As  the  subject  is  both  important  and  interesting, 
it  may  be  well  to  recapitulate  briefly. 
Recapitulation. 

1.  Lime  increases  the  fertility  of  soils  deficient  in  this  element. 

2.  It  causes  the  soil  to  produce  grain  which  yields  more  flour 
and  less  bran,  and  improves  the  quality  of  all  other  crops. 


212 


SCIENTIFIC    AGRICULTURE. 


3.  It  increases  the  effect  of  other  manures  by  hastening  de- 
composition. " 

4.  It  destroys  noxious  insects  and  worms. 

5.  It  destroys  noxious  weeds  and  mosses,  and  gives  rise  to 
sweet  grasses  and  herbage. 

6.  It  prevents  smut  in  wheat  and  other  crops. 

7.  It  hastens  the  maturity  of  the  crop. 

8.  It  neutralizes  the  acidity  of  sour  soils  and  renders  them 
productive. 

9.  It  makes  cold  wet  soils  dryer  and  warmer. 

10.  It  renders  tight  stiff  clays  loose  and  friable 

11.  It  destroys  noxious  gases  and  promotes  health. 

12.  It  stiffens  loose  sandy  soils. 

13.  It  brings  inert  organic  matters  into  a  state  of  fermen- 
tation. 

14.  It  causes  the  evolution  of  carbonic  acid. 

15.  It  serves  directly  as  the  food  of  plants. 

16.  It  causes  the  formation  of  several  salts  in  the  soil. 

COMPOSTS. 

It  was  formerly  supposed,  that  great  advantage  was  derived 
from  the  combination  of  several  different  substances  together, 
and  forming  what  are  called  composts.  The  recipes  for  these 
compounds  are  numerous,  and  go  to  prove  that  the  diswvcry 
of  a  good  compost  requires  but  little  scientific  or  practical  skill. 
AVhen  a  compost  heap  is  made  up  of  several  materials  which 
are  all  separately  good  manures,  it  follows  of  necessity  that 
the  resulting  compound  must  be  a  good  fertilizer.  But  it  is 
impossible  to  supply  any  more  in  this  way  than  if  these  seve- 
ral ingredients  were  applied  to  the  soil  separately.  And  a 
little  knowledge  of  chemistry  w^ill  show  that  by  this  means, 
no  new  elements  can  be  generated.  Neither  can  any  new  pro- 
perty be  developed  which  could  not  be  done  by  their  separate 
action.  -We  see  that  whenever  a  substance  which  has  little  or 
no  fertilizing  power,  is  in  this  way  manufactured  into  a  good 


SCIENTIFIC    AGRICULTURE.  213 

manure,  it  is  done  at  the  expense  of  some  powerful  fertilizer 
which  is  diluted  by  the  mixture,  and  consequently  loses  just 
as  much  of  its  efficacy  as  the  other  gaiss.  Thus,  although 
this  process  serves  to  dilute  and  extend  manures  which  are 
too  powerful  or  too  expensive,  it  absolutely  supplies  none. 

Now,  although  it  is  evident  that  this  method  does  not  aug- 
ment in  the  slightest  degree,  our  quantity  of  available  ma- 
nure,— yet  it  has  several  advantages.  Caustic  lime  and  wqpd 
ashes  are  sometimes  too  strong  for  young  and  tender  vegeta- 
tion ;  and  when  this  is  the  case,  the  object  of  their  use  is 
much  better  attained  by  mixing  and  diffusing  them  through 
some  other  substance,  such  as  saw-dust,  sand,  barn  manure  or 
humus,  or  allowing  them  to  lie  in  a  heap  together  with  any 
vegetable  matters,  such  as  leaves,  straw,  chaff,  rotten  wood  or 
turf;  or  with  animal  matters;  until  decomposition  is  completed. 

Another  advantage  is,  that  a  manure  which  is  valuable  and 
scarce,  as  guano,  poudrette,  and  some  chemical  salts,  may  be 
extended  by  mixture  so  as  to  be  applied  to  a  much  larger  space 
than  would  be  practicable  if  used  singly.  Thirdly,  this  mode 
enables  the  agriculturist  to  spread  his  manure  on  the  soil  more 
even  and  uniformly.  And  lastly,  by  making  compost  we  are 
enabled  to  hasten  the  final  decay  of  animal  and  vegetable 
matters,  so  as  to  gain  considerable  time.  By  mixing  quicklime 
with  barn  manure,  straw,  leaves,  &c.,  decomposition  goes  on 
more  rapidly,  and  these  substances  are  transformed  to  availa- 
ble manures  in  a  comparatively  short  space  of  time.  But 
much  discretion  is  necessary  in  this  respect,  otherwise  some 
valuable  elements  are  wasted  ;  the  object  is  to  fix  and  retain 
the  volatile  elements — and  not  to  dissipate  them.  A  great 
objection  to  composts  is,  the  amount  of  labor  retired  in  ma- 
king, turning,  and  transporting  them  to  the  fields. 

No  definite  formula  can  with  any  propriety  be  given  for 
making  composts,  as  the  agriculturist  must  determine  for  him- 
self in  each  particular  case,  as  to  what  elements  his  fields  most 


214  SCIENTIFIC    AGRICULTURE. 

require,  and  also  his  time  and  the  resources  at  his  command. 
With  these  considerations,  and  an  adequate  knowledge  of  his 
business,  he  will  be  able  to  make  a  more  judicious  disposition 
of  his  manures  than  by  the  aid  of  any  prescribed  rules  which 
can  be  laid  down  in  books. 


CHAPTER  VII. 


TABLE  OF  THE  COMPARATIVE  VALUE  OF  MANURES, 

FROM  ANALYSES  BY  MESSRS.  PAYEN  AND  BOUSSINGAULT. 


Kind  of  Manure. 

M 

~  /: 

i-  -° 

fi 

>  i—  i 

Nitrog 
00  of  ir 

Dry. 

en  in 

latter. 

Wet. 

Q,ual'y 
ding  to 

Dry. 

accor- 
state. 

Wet. 

Squival'nt 
ccord.do. 

Dry.  i  Wet 

Farm-yard  manure, 

79.3 

1.05    0.41 

100 

100 

100 

100 

Water  from   do. 

99.6 

1.54    0.06 

78 

2 

127 

68 

Wheat  straw, 

19.3 

0.30    0.24 

15 

60 

650 

167 

Rye  straw, 

12.2 

0.20    0.17 

10 

42.5 

975  235 

Oat  straw, 

21.0 

0.36 

0.28 

18 

70 

542 

143 

Barley  straw, 

11.0 

0.26 

0.23 

13 

57.5 

750 

174 

Wheat  chaff, 

7.6 

0.94 

0.85 

48 

212.5 

207 

47 

Pea  straw, 

8.5 

1.95 

1.79 

1001447.5 

100 

22 

Buckwheat  straw, 

11.6 

0.54 

0.48 

27 

120 

301 

83 

Dried  potato  tops, 

12.9 

0.43 

0.37 

22 

92.5 

453 

108 

Oak  leaves, 

25.0 

1.57 

1.18 

80 

293 

125 

34 

Beech  leaves, 

39.3 

1.91 

1.18 

78 

294 

102     34 

Burnt  sea  weed, 

3.8 

0.40 

0.38 

20       95 

488|  105 

Oyster  shells, 

17.9 

0.40 

0.32 

20 

80 

488J  125 

Sea-side  marl, 

1.0 

0.52 

0.51 

26.5 

128 

377 

78 

Oak  saw-dust, 

26.0 

0.72 

0.54 

36 

135 

250 

74 

Oil  cake  of  linseed, 

13.4 

6.00 

5.20 

307 

1300 

33 

8 

Refuse  of  cider  apples 

6.4 

0.63 

0.59 

32 

147 

309 

68 

Cow's  ordure, 

85.9 

2.30 

0.32 

117 

80 

84 

125 

Cow's  urine, 

88.3 

3.80 

0.44 

194 

110 

51  1    91 

Excrements  of  horse, 

75.3 

2.21 

0.55 

113  137.5 

88 

73 

Urine  of              do. 

79.1 

12.50 

2.61 

641  652.5 

15.5 

15.3 

Excrements  of  pig, 

8.14 

3.37 

0.63 

172J157.5 

58 

63 

216 


SCIENTIFIC    AGRICULTURE. 


Kind  of  Manure. 

B.» 

».£ 

|i 

Nitrogen  in 
100  of  matter. 

dual')-  accor- 
ding to  state. 

Equivalent 
accord.  do. 

Dry. 

Wet. 

Dry. 

Wet. 

Dry. 

Wet 

Excrements  of  sheep, 

63.0 

2.99 

Lll 

153 

277.5 

65 

36 

Do.         of  goat, 

46.0 

3.93 

2.16 

201 

540 

5018.5 

Poudrette, 

12.5 

4.40 

3.85 

225 

962 

44*10.3 

Urine  of  public  vats, 

9.6 

17.56 

16.83 

900 

4213 

111   2.3 

Excrements  of  pigeons, 

9.6 

9.02 

8.30 

462 

2075 

21.5 

5.0 

Guano, 

19.6 

6.20 

5.00 

323 

1247 

31.5 

80 

Dried  muscular  flesh, 

8.5 

14.25 

13.04 

730 

3260 

13.5 

3 

Liquid  blood,                  ,81.0 

2.95 

795 

736 

13.3 

Fresh  bones, 

30.0 

6.22 

1554 

6.5 

Dregs  of  glue, 

33.6 

5.63 

3.73 

288.4 

933.5 

35 

11 

•Sugar  refiners'  scum, 

67.0 

1.58 

0.54 

81 

134 

127 

75 

Horn  shavings, 

9.0  15.78  14.36 

809 

3590 

12.3 

3.0 

Wood  soot, 

5.6!    1.31 

1.15 

67 

287.5 

149 

35 

TABLES  OF  ANALYSIS. 

Talks  showing  the  relative  proportions  of  inorganic  com- 
pounds In  the  ashes  of  several  cultivated  plants. 
The  tables  are   taken  from   Prof.  Johnston's  Agricultural 
Chemistry, — and  are  supposed  to  be  nearly  correct:  analysis 
of  different  varieties  and  qualities  of  the  same  plants,  vary- 
slightly  ;    but  still,  for  all  practical  purposes,  the  tables  here 
given  are  sufficiently  accurate,  being  probably  as  near  the  real 
constitution  of  them,  as  it  is  possible  to  obtain. 

ASH    OF    WHEAT. 

According  to  Sprengel's  analysis,  1000  Ibs.  of  wheat  leave 
11.77  Ibs.  of  ashes,— and  1000  Ibs.  of  straw  leave  35.18  Ibs. 
of  ash.  after  burning. 


This  ash  consists  of 

Potash, 
Soda, 
Lime, 
Magnesia, 


Grain  of  Wheat. 
2.25  Ibs. 
2.40 
0.96 
0.90 


Straw  of  Wheat. 
0.20  -Ibs. 
0.29 
2.40 
0.32 


SCIENTIFIC   AGRICULTURE. 


21T 


ASH  OF  WHEAT — Continued. 

Grain  of  Wheat.  Straw  of  Wheat. 


Alumina  and  a  trace  of  Iron,  0.26  Ibs. 

Silica,  4.00 

Sulphuric  acid,  0.50 

Phosphoric  acid,  0.40 

Chlorine,  0.10 


11.77  Ibs. 


0.90  Ibs. 
28.70 
0.37 

1.70 
0.30 

35.18  Ibs. 


ASH    OF    BARLEY. 

100  of  grain  of  barley  leaves  23.49  Ibs, — 1000  Ibs.  of  straw 
52.42  of  ash. 


Grain. 

Straw, 

Potash, 

2.78 

1.80 

Soda, 

2.90 

0.48 

Lime, 

1.06 

5.54 

Magnesia, 

1.80 

0.76 

Alumina, 

0.25 

1.46 

Oxide  of  iron, 

a  trace 

0.14 

Oxide  of  manganese, 

0.20 

Silica, 

11.82 

38.56 

Sulphuric  acid, 

0.59 

1.18 

Phosphoric  acid, 

2.10 

1.60 

Chlorine, 

0.19 

0.70 

23.49  Ibs.     52.42  Ibs. 

ASH    OF    OATS. 

1000  Ibs.  of  the  grain  of  oats  contain  25.80  Ibs. — and  of 

straw,  57.40  Ibs.  of  ash. 

Grain. 

Potash,  1.50 

Soda,  1.32 

Lime,  0.86 


Magnesia, 
Alumina, 


0.67 
0.14 


Straw. 
8.70 
0.02 
1.52 
0.22 
0.06 


19 


218 


SCIENTIFIC   AGRICULTURE. 


ASH  OP  OATS — Continued. 


Oxide  of  iron 
Oxide  of  manganese, 
Silica, 

Sulphuric  acid, 
Phosphoric  acid, 
Chlorine, 


Grain. 

Straw. 

0.40 

0.02 

0,02 

19.76 

45.88 

0.35 

0,79 

0.70 

0.12 

0.10 

0.05 

25.80  Ibs.    57.40  Ibs. 


5.32 


ASH    OF  RYE. 

1000  Ibs.  of  rye  straw  contain  27.93  Ibs.,  and  of  grain  10.40 

Ibs.  of  ash. 

Grain. 
Potash, 
Soda, 

1.22 

1.78 

0.24 

0.42 

0.34 

1.64 


Lime, 

Magnesia, 

Alumina, 

Oxide  of  iron, 

Oxide  of  manganese, 

Silica, 


).24  ) 
).42  f 


Straw. 
0.32 
0.11 
1.78 
0.12 

0.25 


Sulphuric  acid, 
Phosphoric  acid, 
Chlorine, 


0.23 
0.46 
0.09 


22.97 
1.70 
0.51 
0.17 


10.40  Ibs.       27.93  Ibs. 

ANALYSIS    OF   PEAT   BY   BOUSSINGAULT. 


Silica, 
Alumina, 
Lime, 
Magnesia, 
Oxide  of  iron, 
Potash  and  Soda, 


65.5 
16.2 
6.0 
0.6 
3.7 
2.3 


SCIENTIFIC  AGRICULTURE.  219 

ANALYSIS    OF   PEAT,   BY   BGUSSINQAULT — Continued. 

Sulphuric  acid,  5.4 

Chlorine,  0.3 

100.0 

ANALYSIS  OF   COAL   ASHES    BY  BOUSSINGAULT. 

Argillaceous  matter  insoluble  in  acids,  62 

Alumina,  5 

Lime,  6 

Magnesia,  8 

Oxide  of  manganese,  3 

Oxide  and  sulphuret  of  iron,  16 

100 

ASH    OF   THE    BEAN   AND   PEA. 

100Q  Ibs.  of  seed  and  straw,  dried,  contain — 


Field  Bean. 

Field  Pea. 

Seed.    Straw. 

Seed.  Straw. 

Potash, 

4.15     16.56 

8,10     2.35 

Soda, 

8.16'     0.50 

7.39 

Lime, 

1.65       6.24 

0.58  27.30 

Magnesia, 
Alumina, 

1.58       2.09 
0.34       0.10 

1.36     3.42 
0.20     0.60 

Oxide  of  iron, 

0.07 

0.10     0.20 

Oxide  of  manganese, 
Silica, 

0.05 
1.26       2.20 

0.07 
4.10     9.96 

Sulphuric  acid, 
Phosphoric  acid, 
Chlorine, 

0.89       0.34 
2.92       2.26 
0.41       0.80 

0.53     3.37 
1.90     2.40 
0.38     0.04 

21.36     31.21  24.64  49.71 

ASH  OF  THE  TURNIP  AND  POTATO. 

10,000  Ibs.  of  the  roots,  stalks  and  leaves,  when  taken  before 
drying,  contain — 


220 


SCIENTIFIC   AGRICULTURE. 


Potato. 

Turnip. 

Roots. 

Tops. 

Roots. 

Leaves. 

Potash, 

40.28 

81.9 

23.86 

32.3 

Soda, 

23.34 

00.9 

10.48 

22.2 

Lime, 

3.31 

129.7 

7.52 

62.0 

Magnesia, 

3.24 

17.0 

2.54 

05.9 

Alumina, 

0.50 

00.4 

0.36 

00.3 

Oxide  of  iron, 

0.32 

00.2 

0.32 

01.7 

Oxide  of  manganese, 

Silica, 

0.84 

49.4 

3.88 

12.8 

Sulphuric  acid, 

5.40 

04.2 

8.01 

25.2 

Phosphoric  acid, 

4.01 

19.7 

3.67 

9.8 

Chlorine, 

1.60 

05.0 

2.39 

8.7 

82,83    308.4  63,03  180.9 

ASH  OF  THE  CARROT  AND  PARSNEP. 


Carrot. 

Parsnep. 

Potash, 

53.33 

20.79 

Soda, 

9.22 

7.02 

Lime, 

6.57 

4.68 

Magnesia, 

3.84 

2.70 

Alumina, 

0.39 

0.24 

Oxide  of  iron, 

0.33 

0.05 

Oxide  of  manganese, 

0.60 

Silica,    * 

1.37 

0.84 

Sulphuric  acid, 

2.70 

5.40 

Phosphoric  acid, 

5.14 

4.01 

Chlorine, 

0.70 

1.60 

66.19  82.83 

ASH    OF    GRASS    AND    CLOVER. 

100  Ibs.  of  dry  hay  and  clover  contain — 

Rye  Grass.    Red  Clover. 


Potash, 
Soda, 


8.81 
3.94 


19.95 
5.29 


SCIENTIFIC  AGRICULTURE. 


221 


ASH  OF  GRASS  AND  CLOVER — Continued. 


Lime, 

Magnesia, 

Alumina, 

Oxide  of  iron, 

Oxide  of  manganese, 

Silica, 

Sulphuric  acid, 

Phosphoric  acid, 

Chlorine, 


7.34 
0.90 
0.31 


27.72 
3.53 
0.25 
0.06 


27.80 
3.33 
0.14 


3.61 
4.47 
6.57 
3.62 


52.86  74.78 

The  practical  inferences  from  these  tables  are, — first — the 
kind  of  soil  in  which  each  will  grow  best, — second — the  kind 
of  inorganic  matter  necessaiy  to  be  supplied  artificially, — 
third— their  nutrient  properties,  and  the  kind  of  stock  they 
are  best  adapted  to  nourish.  ;v 

The  following  table  from  "  Liebig's  Agricultural  Chemistry," 
shows  the  relative  proportions  of  potash,  lime  and  silica  in 
several  cultivated  plants. 

SILICA   PLANTS. 


Oat  straw  and  seeds, 
Wheat  straw, 
Barley  straw  and  seeds, 
Rye  straw, 
Good  hay, 

Tobacco, 
Pea  straw, 
Potato  tops, 
Meadow  Clover, 


ills  of  Potash     Salts  of  Magne- 
and  Soda.        sia  and  Lime. 

34.00 

4.00 

22.50 

7.20 

s,     19.00 

25.70 

18.65 

16.52 

6.00 

34.00 

LIME    PLANTS. 

24.34 

67.44 

27.82 

63.74 

4.20 

51.40 

39.20 

56.00 

19* 

Silica. 
62.00 
61.50 
55.30 
63.89 
60.00 

8.30 

7.31 

63.40 

4.90 


222 


SCIENTIFIC   AGRICULTURE. 


Wheat. 
37.72 

Oats. 
19.12 

Barley. 
20.70 

Rye. 

37.21 

1.93 

10.41 

3.36 

2.92 

9.60 

9.98 

10.05 

10.13 

1.36 

5.08 

1.93 

0.82 

1.25 

9 

9 

9 

49.32 

46.26 

40.63 

47.29 

0.17 

0.26 

1.46 

3.07 

21.99 

0.17 

POTASH  PLANTS —  Continued. 

Corn  stalks,  72.45  6.50  18.00 

Turnips,  81.60  18.40 

Beetroots,  88.00  12.00 

Potatoes,  85.81  14.19 

The  following  table  from  Johnston,  shows  the  composition  of 
the  ashes  of  several  grains  without  the  straw. 

Potash  and  soda, 
Lime, 
Magnesia, 
Oxide  of  iron, 
Oxide  of  manganese, 
Phosphoric  acid, 
Sulphuric  acid, 
Silica, 

101.35       93.92       98.92     100 

There  appears  to  be  some  mistake  in  the  figures  of  this 
table,  as  will  be  seen  on  adding  up  the  columns ;  but  still,  for 
want  of  a  more  accurate  one  we  must  take  this  as  it  is,  being 
sufficiently  accurate  for  all  practical  purposes. 

ASHES  OF  THE  FAECES  OF  THE  HORSE  \  ANALYSIS  OF  JACKSON. 

Phosphate  of  lime,  5.00 

Carbonate  of    do.,  18.75 

Phosphate  of  magnesia,  36.25 

Silicic  acid/  40.00 

100. 

URINE  OF  THE  HORSE  '.    ANALYSIS  OF  YAUQUELIN. 

Carbonate  of  lime,  1.1 

Carbonate  of  soda, 
Hippurate  of    do. 


.9 
2.4 


Muriate  of  potash, 

Urea, 

Water, 


.7 
44-0 


50.0 


SCIENTIFIC    AGRICULTURE.  223 

ASHES  OF  THE  FAECES  OF  THE  COW :   ANALYSIS  OF  IIAIDLEN. 

Phosphate  of  lime,  10.9 

Phos.  magnesia,  10.0 

Phos.  iron,  8.5 

Carbonate  of  potash,  8.5 

Sulphate  of  lime,    •  3.1 

Silicic  acid,  63.7 

Loss,  2.3 

107.0 

URINE  OF  THE  COW  :    ANALYSIS  OF  BRANDE. 

Muriate  of  potash  and  ammonia,    1.5 
Sulphate  of  potash,  0.6 

Carbonate  of  potash,  0.4 

Phosphate  of  lime,  0.3 

Urea,  0.4 

Water,  96.8 


100 

ASHES  OF  HUMAN  FJ2CES  !    ANALYSIS  OF  BERZELIUS. 

Sulphate  of  lime  and  phosphate  of  lime  and  magnesia,  67 
Sulphate  of  soda  and  potash  and  phos.  of  soda,  5 

Carbonate  of  soda,  5 

Silicic  acid,  11 

Carbon  and  loss,  12 

100 

HUMAN  URINE  :    ANALYSIS  OF  BERZELIUS. 

Urea,  30.10 
Lactic  acid  (  ?)  lactate  of  ammonia  (  ?)  extractive 

animal  matter,  17.14 

Uric  acid,  1.00 

Mucus,  0.32 

Sulphate  of  potash,  37.01 

Sulphate  of  soda,  3.16 

Phosphate  of  soda,  2.94 


224  SCIENTIFIC   AGRICULTURE. 

HUMAN  URINE —  Continued. 
Muriate  of  soda, 

Phosphate  of  ammonia, 
Phosphate  of  magnesia  and  lime, 
Muriate  of  ammonia, 
Silicic  acid, 
Water, 

1000 

GUANO  :    ANALYSIS  OF  VOLKEL. 

Muriate  of  ammonia,  4.2 

Oxalate,           do.  10.6 

Urate              do.  9.0 

Phosphate       do.  6.0 

Sulphate  of  potash,  5.5 

Sulphate  of  soda,  3.8 

Phosphate  of  ammonia  and  lime,  2.6 

Phosphate  of  lime,  7.0 

Oxalate  of         do.  14.3 

Residue  soluble  in  uric  acid,  4.7 
Loss,  (water,  ammonia  and  organized  matter,)     32.3 


100 

BONES  OF  THE  OX :  ANALYSIS  OF  BERZELIUS. 

Animal  matter,  (gelatine,)  33.30 

Soda  with  common  salt,  1.20 

Carbonate  of  lime,  11.30 

Phosphate  of    do.  51.04 

Fluoride  of  calcium,  (?)  2.00 

Phosphate  of  magnesia,  1.16 

100 

COAL  SOOT  I  ANALYSIS  OF  BRACONNOT. 

Ulmic  acid,  302.0 
A  reddish  brown  substance  containing  nitrogen, 

and  yielding  ammonia  when  heated,  200.0 

Asboline,  5.0 


SCIENTIFIC    AGRICULTURE. 


225 


COAL  SOOT — Continued. 

Carbonate  of  lime  with  a  trace  of  magnesia,  146.6 

Acetate  of  lime,  56.5 

Sulphate  of  lime,  50.0 

Acetate  of  magnesia,  5.3 

Phosphate  of  lime,  with  a  trace  of  iron,  15*0 

Chloride  of  potassium,  3.6 

Acetate  of  potash,  41.6 

Acetate  of  ammonia,  2.0 

Silica,  9.5 

Charcoal  powder,  38.5 

Water,  125.0 

100 

WOOL,  HAIR,  HORN  \     ANALYSIS  OF  JOHNSTON. 


Carbon, 

Hydrogen, 

Nitrogen, 

Oxygen  and  sulphur, 


Wool. 

Hair. 

Horn. 

50,65 

51.53 

51.99 

7.03 

6.69 

6.72 

17.71 

17.94 

17.28 

24.61 

23.84 

24.01 

100 


100 


100 


DRY  OX  BLOOD  AND  MUSCULAR  FLESH  I    ANALYSIS  OF  PLAYFAIR 
AND    BOECKMAN. 
Dry  Flesh. 

Carbon,  51.83 

•*    Hydrogen,  7.57 

Nitrogen,  15.01 

Oxygen,  21.37 

Ashes,  4.23 

100 

Remark. — We  have,  all  through  the  course  of  this  treatise, 
adhered  to  the  principle  that  nature  preserves  a  uniformity  in 


226  SCIENTIFIC   AGRICULTURE. 

the  execution  of  all  her  laws,  and  that  she  does  nothing  by 
accident.  And  whenever  we  find  an  apparent  exception  to 
this  principle,  it  is  evident  that  our  knowledge  is  deficient  or 
our  conclusions  erroneous. 

Hence,  although  plants  may  be  made  to  maintain  a  transi- 
tory and  sickly  existence  without  all  the  usual  elements,  and 
to  absorb  both  by  their  leaves  and  roots,  substances  unneces- 
sary and  pernicious  to  their  growth,  still  from  the  uniformity 
of  the  elements  and  their  proportions,  as  shown  by  analysis  of 
the  plants  and  the  soils  in  which  they  thrive  best,  we  are  com- 
pelled to  conclude,  that  each  and  all  of  these  elements,  are  in- 
dispensible  to  their  healthy  growth  and  maturity.  And  who- 
ever practically  disregards  this  principle,  and  hangs  his  hope 
of  success  on  some  contingent  circumstance,  must  correct  his 
error  at  his  own  cost. 


CHAPTER  VIII. 


ANALYSIS    OF   SOILS. 

THE  agriculturist  may,  by  long  experience  and  close  obser- 
vation of  the  character  and  productions  of  his  lands,  become 
acquainted  with  their  general  character  and  fertility, — and 
also  what  plants  are  best  adapted  to  them.  But  it  is  desirable 
that  a  more  accurate  knowledge  of  the  elementary  constitution 
and  the  relative  proportions  of  those  elements  which  constitute 
the  food  of  plants,  should  be  attained. 

The  only  direct  and  certain  means  of  arriving  at  this  result 
is  chemical  analysis.  Without  this  process,  it  could  only  be 
known  by  a  trial  of  various  crops  upon  different  soils,  whether 
they  were  adapted  to  them  or  not:  and,  in  order  to  determine 
the  value  of  soils  in  this  way,  several  crops  and  much  labor 
might  be  lost  in  unsuccessful  experiments. 

Analysis  of  plants  shows  with  absolute  certainty  what  sub- 
stances they  have  drawn  from  the  soil  and  atmosphere  for 
food;  these  substances  vary  in  different  plants,  both  in  their 
nature  and  proportions:  the  same  is  also  true  in  relation  to 
the  elementary  composition  of  soils.  No  two  plants  and  no 
two  soils  have  precisely  the  same  chemical  composition.  The 
absence  of  a  single  element  in  a  soil  may  render  it  totally  bar- 
ren for  a  particular  crop,  while  it  may  produce  some  others  in 
great  abundance. 

A  chemical  difference  in  two  soils,  which  might  appear 


228  SCIENTIFIC    AGRICULTURE. 

insignificant,  would,  by  experiment,  be  found  to  alter  entirely 
their  relative  agricultural  value. 

By  referring  to  tables  of  the  analysis  of  plants,  and  then 
analyzing  the  soil,  we  can  see  at  once  what  plant  the  soil  is 
adapted  to  produce.  A  soil  containing  all  the  organic  and 
inorganic  elements  of  a  particular  plant,  may  be  supposed 
capable  of  producing  the  plant:  but  a  soil  deficient  in  one  or 
more  of  these  elements  cannot  be  expected  to  yield  a  crop. 
A  soil  containing  very  little  silica  could  not  yield  grass,  but 
might  still  contain  enough  for  a  crop  of  turnips.  . 

An  exact  analysis  of  the  quality  of  a  soil,  with  the  quantity 
of  each  element,  requires  the  skill  of  a  practical  chemist,  and 
the  apparatus  of  a  laboratory:  but  the  most  important  qualities 
of  a  soil  may  be  determined  by  a  few  plain  and  simple  experi- 
ments, which  are  easily  made  by  any  one,  whether  acquainted 
with  chemistry  or  not 

The  soil  is  made  up,  as  before  said,  of  various  proportions  of 
animal,  vegetable,  mineral,  earthy  and  gaseous  matters.  As  a 
general  rule,  the  earthy  part  of  the  soil  is  estimated  at  from 
90  to  96  per  cent  The  salts  of  these  earthy  matters  are  in 
small  quantities.  The  amount  of  vegetable  matter  varies 
greatly  in  different  soils:  in  some,  as  in  peat  and  muck  soils,  it 
constitutes  from  one  half  to  three  fourths  of  their  entire 
weight ;  while  in  sand  and  clay  soils,  it  amounts  to  only  from 
one  to  five  per  cent  The  principal  bulk  of  all  soils,  (except 
peat,  humus  and  muck  soils,)  is  sand,  clay  and  lime ;  and  on 
the  proportions  of  these,  their  peculiar  properties,  both  chemi- 
cal and  physical,  depend.  The  fertility  of  a  soil  is  not  depen- 
dent upon  any  one  of  these,  but  upon  the  proportions  and 
state  of  mechanical  division  of  all  the  other  necessary  elements. 
The  mixture  of  sand  and  lime  with  the  other  elements,  (except 
the  alumina,)  is  usually  entirely  mechanical:  in  the  various 
kinds  of  clay,  the  silex  and  alumina  are  often  chemically  com- 
bined, constituting  a  silicate  of  alumina. 


SCIENTIFIC   AGRICULTURE.  229 

The  first  process  in  the  analysis  of  a  soil  is  to  weigh  a  given 
quantity  with  apothecaries'  scales;  it  should  then  be  spread 
out  on  a  piece  of  clean  paper  and  subjected  to  a  heat  not  suffi- 
ciently high  to  burn  the  vegetable  matters  which  it  contains, 
until  thoroughly  dried :  after  drying,  the  soil  should  be  again 
accurately  weighed,  and  the  second  weight  subtracted  from 
the  first,  when  the  remainder  will  show  the  amount  of  water 
lost 

To  find  the  amount  of  organic  matter  which  it  contains,  put 
the  dried  soil  into  an  earthen  crucible  and  heat  it  over  a  fire 
to  "redness,  till  the  organic  matter  is  burned  out  and  the  ash 
only  remains ;  after  cooling,  it  should  be  again  weighed, — the 
loss  by  burning  shows  the  amount  of  organic  matter  it  con- 
tained, allowing  a  trifle  for  the  charcoal  which  remains  with 
the  earthy  part  If  a  black  soil  loses  nothing  by  burning,  it 
probably  derives  it  color  from  black  oxide  of  iron  or  graphite. 

To  detect  humic  acid,  boil  a  small  quantity  of  peat  or  muck 
in  a  solution  of  carbonate  of  soda,  until  it  attains  a  brown 
color,  then  add  muriatic  acid  till  the  solution  has  a  distinctly 
sour  taste,  when  brown  flocks  of  humic  acid  will  fall  to  the 
bottom. 

Ulmic  acid  may  be  obtained  from  the  same  soil,  after  the 
humic  acid  is  separated,  by  digesting  it  over  a  gentle  heat  in  a 
solution  of  caustic  ammonia,  and  then  adding  muriatic  acid  as 
before ; — brown  flocks  are  precipitated,  which  are  ulmic  acid. 

To  detect  crenic  and  apocrenic  acids,  digest  a  quantity  of 
soil  in  hot  water  until  organic  matter  is  dissolved  out  sufficient 
to  give  the  water  a  yellow  color.  When  this  solution  is  evapo- 
rated to  dryness,  there  remains  a  brown  residue,  which  con- 
tains the  soluble  saline  matters  of  the  soil,  some  extractive 
matter,  humic  and  ulmic  acids,  and  the  crenic  and  apocrenic 
acids:  these  four  acids  are  all  in  combination  with  alumina 
and  other  bases.  When  this  residue  is  dried  at  220°  F.,  the 
compounds  of  the  humic  and  ulmic  acids  become  insoluble, 

20 


230  SCIENTIFIC   AGRICULTURE. 

while  the  compounds  of  the  crenic  and  apocrenic  acids  remain 
soluble,  and  may  be  separated  by  washing  in  water.  (Johnston.) 
To  detect  the  presence  of  lime,  take  100  grains  of  a  soil  and 
mix  well  with  half  a  pint  of  cold  water,  and  then  add  half  an 
ounce  of  muriatic  acid,  stirring  the  mixture  frequently :  let  it 
stand  a  few  hours  to  settle,  then  pour  off  the  water  and  fill  the 
vessel  with  water  to  wash  out  the  excess  of  acid ;  when  the 
water  is  clear,  pour  it  off,  dry  the  soil  and  weigh  it; — the  loss 
from  the  first  weight  will  show  the  quantity  of  lime  sufficiently 
near  for  all  practical  purposes.  (Gaylord.) 

To  determine  the  amount  of  sand,  take  a  given  quantity  of 
soil  and  boil  it  in  water  till  it  is  thoroughly  incorporated  with 
it,  then  pour  the  whole  into  a  glass  vessel  and  leave  it  till  the 
sand  subsides:  the  clay  remains  in  a  state  of  mixture  with  the 
water,  which  should  be  poured  off  and  the  sand  dried  and 
weighed.  If  the  sand  contains  lime,  it  may  be  separated  by 
muriatic  acid  as  above  directed. 

The  amount  of  clay  may  be  very  nearly  ascertained  by 
evaporating  the  water  which  was  poured  off  of  the  said, — 
the  residue  will  be  mostly  clay. 

To  detect  the  presence  of  oxide  of  iron,  mix  a  quantity  of 
soil  with  water,  pour  on  muriatic  acid  and  stir  the  mixture  ; 
let  it  stand  a  few  hours  and  dip  a  piece  of  oak  bark  into  the 
solution, — if  the  bark  is  colored  brown  or  black,  iron  is  present. 
"  To  detect  the  presence  of  other  salts,  boil  a  portion  of  soil 
in  water,  pour  off  the  water  and  evaporate  it,  when  the  salts 
may  be  obtained  in  crystals. 

If  the  salt  is  a  nitrate,  it  has  a  cool  pungent  taste,  and 
ignites  when  thrown  on  coals  of  fire. 

If  it  be  common  salt,  (muriate  of  soda,)  it  burns  with  a 
crackling  noise,  and  is  also  known  by  its  taste. 

Sulphate  of  soda  puffs  up  by  heat,  gives  off  a  watery  vapor 
and  leaves  a  dry  white  mass." 

These  directions  are  sufficient  to  enable  any  one  to  make  a 


SCIENTIFIC    AGRICULTURE.  231 

rough  analysis  of  a  soil,  which,  although  not  strictly  correct, 
may  be  of  much  service  in  determining  the  general  character 
of  a  farm,  when  a  rigid  and  exact  analysis  cannot  be  obtained. 
We  give  below  two  tables, — one  showing  the  composition  of  a 
barren,  and  the  other  of  a  fertile  soil.  Taking  the  mineral 
constituents  of  plants  as  a  basis  on  which  to  predicate  our  rea- 
soning in  relation  to  the  productive  value  of  soils,  we  see  at 
once,  that  one  of  these  tables  shows  a  soil  rich  in  all  the 
elements  of  fertility,  while  the  other  exhibits  one  almost  irre- 
deemably barren. 

ANALYSIS  OF  A  NEW    SOIL   ON   THE    BANKS    OF   THE    OHIO    RIVER, 
POSSESSING   GREAT    FERTILITY. 

Quartz  sand  and  silicates,  87.143 

Alumina,  5.666 

Oxides  of  iron,  2.220 

Oxides  of  manganese,  0.360 

Lime,  0.564 

Magnesia,  0.312 

Potash  and  soda,  0.145 

Phosphoric  acid,  0.060 

Sulphuric  acid,  0.027 

Chlorine  in  common  salt,  0.026 

Humie  acid,  1.304 

Insoluble  humus,  1.072 

Organic  matters  containing  nitrogen,  1.011 

Carbonic  acid  united  to  the  lime,  0.080 

ANALYSIS  OF  A  SANDY  SOIL,  UNFIT  FOR  CULTIVATION. 

Silica  and  quartz  sand,  96.000 

Alumina,  0.500 

Oxides  of  iron,  2.000 

Oxides  of  manganese,  trace. 

Lime,  0.001 

Magnesia,  trace. 


232  SCIENTIFIC   AGRICULTURE. 

ANALYSIS —  Continued. 

Potash,  do. 

Soda,  do. 

Phosphoric  acid,  do. 

Sulphuric  acid,  do. 

Carbonic  acid,  


Chlorine,  trace. 

Humic  acid,  0.200 

Insoluble  humus,  1.299 
Water, 

100 

Chemically  considered,  a  soil  must  contain  all  the  inorganic 
elements  which  plants  require,  and  none  that  are  injurious  to 
them.  If  the  addition  of  a  certain  manure  render  a  soil  more 
fertile,  it  is  evident  that  the  soil  was  deficient  in  one  or  more 
of  those  substances  which  it  furnished.  If  the  addition  of  a 
given  manure  or  salt  to  a  defective  soil,  fail  to  improve  its  fer- 
tility, it  is  because  enough  of  this  substance  is  already  present, 
or  because  some  other  substance  is  wanting  to  render  this 
application  available.  A  soil  may  sometimes  show  more  or 
less  fertility  for  certain  crops  than  analysis  would  indicate,  on 
account  of  some  mechanical  and  physical  conditions  :  in  this 
way  the  supply  of  certain  elements  may  be  cut  off,  although 
they  are  present  in  the  soil :  the  deficiency  of  others  may  also 
be  partially  compensated  by  the  same  causes. 


CHAPTER  IX. 


MECHANICAL  PHILOSOPHY. 

Mechanical  philosophy  treats  of  the  equilibrium  and  motion 
of  bodies:  its  great  object  of  inquiry  is,  into  the  causes  which 
produce  or  prevent  motion,  and  the  manner  in  which  it  takes 
place.  "  That  part  of  mechanics  which  relates  to  the  action  of - 
forces  producing  equilibrium  or  rest,  in  bodies,  is  called  statics; 
that  which  relates  to  the  action  of  forces  producing  motion  is 
called  dynamics" 

The  practical  value  of  this  branch  of  science  consists  in  the 
application  of  a  few  simple  mechanical  powers,  either  single  or 
combined  in  some  kind  of  machinery,  in  overcoming  resistances, 
and  producing  and  applying  motion  to  useful  purposes. 

"  Power  is  the  means  by  which  a  machine  is  moved  and 
force  attained ;  thus  we  have  horse  power,  water  power,  steam 
power,  <fec. 

Force  is  the  means  by  which  bodies  are  set  in  motion,  kept 
in  motion,  and  when  moving  are  brought  to  rest  The  force 
of  gunpowder  sets  a  ball  in  motion  and  keeps  it  moving  until 
the  resisting  force  of  the  air,  and  the  force  of  gravity  bring  it 
to  rest" 

A  few  simple  instruments  or  machines  variously  combined, 
produce  all  the  complicated,  powerful  and  beautiful  pieces  of 
machinery  which  have  ever  been  constructed. 

20* 


234  SCIENTIFIC    AGRICULTURE. 

These  few  elementary  powers  are,  the  lever,  the  wheel  and 
axle,  the  pulley,  the  inclined  plane,  the  wedge  and  the  screw. 

The  lever  is  a  straight  bar  placed  upon  a  supporting  point 
called  a  fulcrum,  with  the  resistance  which  i's  to  be  overcome, 
at  one  end,  and  the  power  applied,  at  the  other. 

The  wheel  and  axle  is  somewhat  more  complex  than  the 
lever  ;  it  consists  of  two  concentric  wheels,  one  of  which  is 
larger  than  the  other,  and  both  revolving  on  a  common  axis. 
•This  power  acts  like  a  succession  of  levers,  and  is  therefore  a 
a  modification  of  the  lever. 

The  pulley  consists  of  a  flat  disc,  with  a  groove  on  the  edge, 
through  which  a  rope  passes,  and  a  hole  in  its  centre,  through 
which  a  fixed  axis  passes,  on  which  it  revolves:  when  several 
pulleys  are  combined,  they  constitute  a  system  of  pulleys,  or  a 
compound  pulley.  The  power  of  a  system  of  pulleys  increases 
in  proportion  to  the  number  of  pulleys  employed. 

The  inclined  plane,  as  its  name  implies,  consists  merely  of  a 
plane  surface,  with  one  of  its  ends  higher  than  the  other,  so 
that  the  plane  forms  an  angle  with  the  horizon. 

The  wedge  may  be  considered  as  two  inclined  planes  with 
their  bases  placed  together,  and  their  apices  forming  an  acute 
point.  The  power  of  the  wedge  depends  upon  its  relative 
length  compared  with  the  width  of  its  base, — or  upon  the  de- 
gree of  taper  from  the  base  to  the  point. 

The  screw  is  the  sixth  mechanical  power,  and  may  be  con- 
sidered a  continuous  spiral  wedge,  or  a  modification  of  the  in- 
clined plane.  The  power  of  the  screw  depends  upon  the  rela- 
tion between  its  circumference  and  the  distance  between  its 
threads. 

OBJECTS  AND  ADVANTAGES  OF  MACHINERY. 

No  actual  power  is  ever  generated  by  machinery ;  force  and 
velocity  may  be  gained,  but  they  are  always  gained  at  the 
expense  of  the  motive  power  applied  to  work  the  machine: 
the  power  and  force  must  always  be  in  exact  proportion  to 


MECHANICAL    PIIILOSOPII V.  235 

each  other,  so  that,  if  one  is  increased,  the  other  is  diminished 
in  the  same  proportion.  Great  velocity  in  a  machine,  or  in  any 
of  its. parts,  is  incompatible  with  great  power  also;  for  whatever 
js  gained  in  speed  is  lost  in  strength, — that  is,  it  is  gained  at 
the  expense  of  power  or  force. 

It  is  not  expected  to  gain  power,  force  and  velocity  at  the 
same  time  by  tho  use  of  any  mechanical  contrivance  whatever, 
— but,  by  taking  a  philosophical  advantage  of  the  few  simple 
mechanical  powers,  to  obtain  one  or  the  other  of  them,  accor- 
ding to  the  labor  to  be  performed. 

The  advantages  of  machinery  are  numerous. 

1.  By  the  aid  of  machinery  we  can  apply  force  to  much 
better  purpose  than  by  our  unassisted  hands. 

2.  A  man  can  perform  a  work  by  its  aid,  to  which  he  would 
be  wholly  incompetent  without  it 

3.  It  often  enables  men  to  exert  their  whole  force,  where 
without  it  they  could  exert  only  a  small  part  of  it. 

4.  It  enables  us  to  employ  animals  in  the  execution  of  many 
kinds  of  work  which  must  otherwise  be  performed  by  man 
himself. 

5.  It  enables  us  to  employ  several  inanimate  motive  powers, 
such  as  water,  steam,  wind," heat,  electricity,  &c. 

6.  Many  manufacturing  operations  are  performed  with  much 
greater  facility  and  exactness  than  they  could  be  by  hand. 

7.  Machinery  saves  a  considerable  part  of  the  materials  used 
in  the  manufacture  of  many  fabrics. 

ON  REGULATING  THE  MOTION  OF  MACHINERY. 

The  motion  of  machinery,  to  operate  to  the  best  advantage, 
should  be  perfectly  regular  and  uniform.  Variations  of  motion 
consist  principally  in  variations  of  power,  weight  or  resistances, 
and  changes  of  velocity  in  different  parts  of  the  machine  itself. 
The  different  instruments  used  to  obviate  these  effects,  and 
secure  uniform  motion,  are  called  regulators.  There  can  be 
little  doubt  that  water,  where  it  is  abundant  and  available, 


236  SCIENTIFIC    AGRICULTURE. 

furnishes  the  most  economical  motive  power,  and  one  which 
propels  machinery  with  greater  uniformity  than  any  other 
which  we  possess. 

Among  the  instruments  used  fcr  modifying  and  regulating 
motion  are,  the  fly  wheel,  governor,  ratchet  wheel,  universal 
joint,  crank,  eccentric  wheel,  arch  head,  pendulum,  knee  joint, 
fusee,  &c. 

Every  part  of  a  machine  ought  to  be  proportioned  to  the 
stress  it  is  to  bear,  and  the  strength  it  requires, — and  should 
be  no  heavier  than  necesssary:  all  parts  should  bear  their 
relative  proportion  of  the  work  and  wear,  so  that  when  the 
machine  fails,  all  parts  shall  be  worn  out.  Every  machine 
should  consist  of  as  few  parts  as  possible ;  because,  when  parts 
are  multiplied,  friction  is  increased  in  the  same  proportion,  and 
the  machine  is  more  liable  to  get  out  of  repair.  All  mechanical 
obstacles  and  errors  have  a  less  ratio  to  the  motion  in  great 
than  in  small  machines ;  the  former,  therefore,  work  with  more 
uniformity  and  exactness,  but  are  proportionally  weaker  and 
more  liable  to  be  broken. 

Motion  and  rest  are  both  equally  accidental  states  of  matter: 
bodies  are  no  more  disposed  to  lie  at  rest  than  to  put  them- 
selves in  motion :  they  maintain  a  state  of  rest  so  long  as  there 
is  an  equilibrium  of  all  the  furces  acting  upon  them ;  and  when 
they  assume  a  state  of  motion,  it  is  because  they  are  acted 
upon  by  some  extrinsic  force,  which  is  stronger  than  the  com- 
bined action  of  all  those  which  tend  to  keep  them  at  rest. 
When  once  in  motion,  bodies  would  continue  moving  forever, 
if  no  force  obstructed  them  to  destroy  the  equiblirum  between 
accidental  resistances  and  the  propelling  force :  in  other  words, 
they  never  would  come  to  rest,  unless  brought  to  rest  by  some 
power  superior  to  that  which  set  them  moving. 

Motion  may  be  absolute  or  relative:  absolute  motion  is  a 
change  of  place  by  a  body,  in  relation  to  some  fixed  point: 


MECHANICAL    PHILOSOPHY.  237 

relative  motion  is  a  change  of  place  by  a  body  in  relation  to 
some  other  body  which  is  in  absolute  motion. 

Simple  motion  results  from  the  action  of  a  single  force  upon 
a  body,  while  compound  motion  is  produced  by  two  or  more 
forces  acting  different  directions.  Motion,  when  once  attained 
would  be  onward  in  a  straight  line  unless  changed  or  destroy- 
ed by  some  force  secondary  to  the  one  by  which  it  was  pro- 
duced :  a  ball  projected  from  a  cannon,  assumes  a  curved  line 
towards  the  earth,  because  acted  upon  by  the  attraction  of 
gravity ;  and  this  sufficiently  strong  to  overpower  the  propel  - 
ling  force  of  the  powder  which  gave  it  motion,  and  finally  bring 
it  to  rest. 

OBSTRUCTIONS  TO  THE  ACTION  OF  MACHINERY. 

Friction  arises  mostly  from  the  elevations  of  one  surface 
entering  into  the  depressions  of  another;  but  partly  also  from 
the  mutual  cohesion  of  the  surfaces. 

Sliding  friction  is  produced  when  pinions  or  axes  revolve  on 
their  support 

Rolling  friction  occurs  when  a  round  ball  or  wheel  rolls 
along  a  surface.  Friction  is  greater  between  two  surfaces  of 
wood  where  their  fibres  lie  parallel  than  where  they  run  across 
each  other:  it  is  also  greater  between  two  surfaces  of  the  same 
metal  than  between  those  of  different  metals :  two  surfaces  of 
iron  would  produce  more  friction  than  one  of  copper  and  one 
of  iron :  cast  steel  is  said  to  be  an  exception  to  this  rule. 

The  ristance  of  friction  may  be  diminished  by  the  use  of  fine 
smooth  and  oily  substances ;  the  particles  of  which  fill  up  the 
cavities  and  lubricate  the  asperities  of  the  surfaces.  For  this 
purpose  oil  is  best  adapted  to  metals  and  tallow  for  wood. 

Extent  of  surface  makes  no  difference,  in  a  given  body,  in 
regard  to  the  amount  of  friction  developed.  Friction  is  in- 
creased between  two  bodies  by  their  remaining  some  time  in 
contact;  in  some  cases  it  does  not  attain  the  maximum  in  four 
or  five  days.  In  the  contact  of  two  metals,  the  friction  attains 


238  SCIENTIFIC    AGRICULTURE. 

its  highest  point  in  a  few  seconds:  two  pieces  of  wood  attain 
their  utmost  friction  in  one  or  two  hours :  when  iron  runs  upon 
oak  the  friction  will  increase  for  four  or  five  days. 

Friction  is  less  after  motion  becomes  well  established  and 
rapid,  than  when  it  first  commences.  The  whole  efficacy  of 
the  screw  depends  upon  the  friction  between  the  threads  of 
the  external  and  internal  screw:  the  screw  being  an  inclined 
plane,  if  there  was  no  friction,  it  would  unscrew,  or  the  inter- 
nal screw  would  descend  by  its  own  gravity  when  placed  ver- 
tically. Query  ?  What  relation  has  the  development  of  fric- 
tion to.  electricity  ? 

The  resistance  of  the  atmosphere,  which  in  some  machines 
must  be  considerable,  is  another  obstruction  to  the  action  of 
machinery.  The  weight  or  gravity  of  a  machine  itself,  or  of 
some  of  its  parts,  is  sufficient  in  some  cases  to  require  a  consi- 
derable part  of  its  power  to  overcome  it. 

STRENGTH    OF    MATERIALS. 

It  is  important,  in  the  construction  of  all  pieces  of  archi- 
tecture and  machinery,  that  the  mechanic  should  know  the 
strength  of  the  materials  which  he  is  to  employ  in  the  work. 
By  strength,  we  understand  the  power  which  a  body  has,  by 
the  cohesive  force  of  its  particles  to  resist  fracture :  stress  is 
the  power  or  tendency  in  a  body  to  produce  fracture  by  its 
own  weight. 

A  joist  eight  inches  wide  and  two  inches  thick,  is  four  times 
as  strong  when  laid  on  its  edge  as  when  laid  on  its  side. 

"  A  triangular  beam  is  twice  as  strong  when  resting  on  its 
broad  base  as  when  resting  on  its  edge." 

"  The  strength  of  a  column  in  the  direction  of  its  length,  is 
directly  proportional  to  the  area  of  its  transverse  section." 

"  Half  the  length  of  a  beam  supported  at  both  ends,  will 
bear  four  times  as  great  a  pressure  as  the  whole  beam ;  and  a 
prop  placed  under  the  centre  of  a  beam  increases  its  strength 
in  the  same  ratio." 


MECHANICAL    PHILOSOPHY. 

The  strength  of  a  beam  increases  from  the  centre  towards 
the  ends  or  points  of  support,  and  the  stress  increases  from 
the.  ends  towards  the  centre;  hence,  a  beam  to  be  equally 
strong  at  every  point,  should  be  eliptical,  or  the  largest  in  the 
middle  and  taper  regularly  towards  both  ends. 

The  strongest  form  in  which  a  given  quantity  of  matter  can 
be  disposed,  is  that  of  a  hollow  cylinder:  this,  however,  is  true 
only  when  the  transverse  sections  of  the  cylinder  are  perfectly 
circular.  In  this  way  nature  economizes  material,  avoids  too 
great  weight,  and  at  the  same  time  augments  strength. 

"A  great  column  is  in  greater  danger  of  being  broken  than 
a  similar  small  one ;  an  insect  can  sustain  a  weight  many  times 
greater  than  itself, — whereas  a  much  larger  animal,  as  a  horse, 
eould  scarcely  carry  another  horse  of  his  own  size." 

It  is  not  regarded  as  safe  to  load  a  stone  structure  with  more 
than  one-sixth  the  amount  of  pressure  which  it  requires  to 
crush  it:  iron  may  be  loaded  to  one-fourth  that  amount  In 
building  bridges,  <fec.,  which  are  to  span  considerable  space 
without  as  much  support  as  might  be  desirable,  it  is  important 
to  calculate  accurately,  both  the  strength  and  stress  of  the 
beams :  bridges  apparently  strong,  and  perfect  in  construction, 
sometimes  fall  by  their  own  weight:  in  such  cases  there  is  an 
unnecessary  violation  of  a  philosophical  principle  of  which  no 
mechanic  should  be  ignorant  For  suspension  bridges,  the 
strongest  material  for  spanning  a  wide  stream  is  cast  steel 
wire, — the  next  strongest  is  malleable  iron,  and  k-ast  of  all 
metals,  lead.  A  piece  of  cast  steel  wire  one-eighth  of  an  inch 
in  diameter  will  sustain  a  weight  of  16,782  pounds;  or  4,931 
feet  of  its  own  length  :  malleable  iron  wire  of  the  same  size, 
9,008,  or  2,467  feet  of  its  own  length:  lead  wire  of  the  same 
size  sustains  only  228  pounds,  or  42  feet  of  its  own  length. 

Of  the  different  kinds  of  wood,  the  strongest  are,  the  ash, 
oak,  teak,  beech  and  larch, — the  strongest  of  these  is  the  ash. 
We  see  by  these  few  facts  in  relation  to  mechanical  philoso- 


240  SCIENTIFIC    AGRICULTURE. 

phy,  that  almost  every  practical  mechanical  operation  can  be 
reduced  to  scientific  rules,  and  the  result  calculated  with 
mathematical  certainty  before  the  work  is  commenced.  We 
see  also  how  much  more  easily  and  economically  many  opera- 
tions might  be  performed,  and  how  much  disappointment  and 
money  might  be  saved  by  a  knowledge  of  this  branch  of  sci- 
ence, to  the  visionary  inventors  of  patent  rights,  the  only  fault 
of  which  is,  that  they  refuse  obstinately  to  perform  any  part 
of  the  work  designed  for  them, — and  the  greatest  misfortune  of 
whose  inventors  is  their  ignorance.  A  knowledge  of  mechani- 
cal philosophy  is  indispensible  to  the  accomplished  mechanic  or 
agriculturist 


GLOSSARY. 


Agriculture,  the  science  and  art  of  productive  farming. 

Affinity,  attraction— that  force  which  causes  two  bodies  of  dif- 
ferent properties  to  unite  and  form  a  compound. 

Annual,  yearly. 

Aerial,  pertaining  to  the  air. 

Axis,  the  centre  or  point  on  which  a  body  does  or  may  revolve. 

Acotyledonous,  without  a  colyledon. 

Appendage,  something  added. 

Albumen,  an  organic  principle  resembling  white  of  eggs. 

Altitude,  height  or  elevation. 

Arterial,  pertaining  to  the  arteries. 

Acerose,  needle  shaped. 

Axillary,  growing  in  the  angle  between  the  stem  and  leaf. 

Arragonite,  a  simple  mineral  composed  of  carbonate  of  lime. 

Ament,  flowers  collected  on  chaff-like  scales  and  arranged  on  a 
slender  stalk. 

Assimilate,  to  become  similar. 

Anemia,  want  of  blood — in  botany  want  of  sap. 

Absorption,  the  act  of  imbibing  or  absorbing.  , 

Anthracite,  a  species  of  mineral  coal. 

Aluminum,  a  metalic  earth,  the  base  of  alum. 

Albite,  a  species  of  feldspar. 

Arseniate,  a  salt  of  arsenic. 

21 


242  GLOSSARY. 

Asbestos,  a  fibrous  incombustible  mineral. 

Analysis,  separating  the  elements  of  a  compound. 

Azure,  sky  blue. 

Alluvium,  the  sediment  of  rivers  such  as  sand,  vegetable  mat- 
ter, mud,  &c. 

Augite,  a  simple  mineral  of  a  dark  green  or  black  color,  found 
as  a  constituent  in  many  volcanic  rocks. 

Amygdaloid,  one  of  the  trap  rocks  through  which  are  scatter- 
ed agates  and  simple  minerals. 

Agate,  a  translucent  silicious  mineral  of  many  varieties. 

Apocrenic  acid,  an  acid  found  in  peat  and  humus  soils. 

Atmosphere,  the  air  which  we  breathe. 

Aggregate,  the  sum  of  several  particulars. 

Anhydrous,  destitute  of  water. 

Aurora  Borealis,  Northern  Lights. 

Aqueous,  wateiy. 

Aerolite,  a  meteoric  stone  falling  through  the  air. 

Alternate,  leaves  growing  on  opposite  sides  of  the  stem  at  dif- 
ferent distances,  but  not  opposite  each  other,  are  alternate. 

Alburnum,  sap-wood. 

Accretion,  increasing  in  size  by  the  addition  of  new  matter. 

Alchemy,  the  pretended  science  from  which  chemistry  origina- 
ted :  its  operations  consisted  in  trying  to  change  the  baser 
metals  into  gold ;  to  find  a  universal  solvent  and  a  remedy 
for  all  diseases. 

Attenuation,  the  act  of  making  fine,  thin,  minute. 

Angle  of  incidence,  the  angle  at  which  a  moving  body  strikes 
another. 

Angle  of  reflection,  the  angle  at  which  a  moving  body  leaves 
or  bounds  from  another. 

Aquafortis,  nitric  acid. 

Aqua-ammonia,  spirit  of  hartshorn. 

Acrid,  sharp,  pungent,  biting. 

Acid,  sour,  having  chemical  properties  opposite  to  alkalies. 


GLOSSARY.  243 

Alkali,  in  common  language,  lye. 

Apotheme,  extractive  matter. 

Adjective  colors,  such  as  require  a  mordant 

Alizarine,  the  basis  of  the  red  coloring  principle. 

Arable,  fit  for  tillage  or  cultivation. 

Avidity,  greediness,  eagerness. 

Asboline,  one  of  the  elements  of  soot 

Botany,  the  science  of  plants. 

Boulder,  a  rounded  fragment  of  rock  lying  on  the  surface. 

Blowpipe,  an  instrument  used  in  chemical  experiments. 

Bole,  a  species  of  reddish  earth. 

Bitwnenization,  the  process  of  furnishing  bituminous  coal 

Biennial,  once  in  two  years. 

Biternate,  twice  ternate, — two   petioles,  each  bearing   three 

leaves. 
Barometer,  an  instrument  for  measuring  the  pressure  of  the 

atmosphere. 
Base,  the  substance  which  combines  with  an  acid  to  form  a 

salt 
Bed,  a  term  used  in  Geology  to  denote  the  extent  of  a  stratum 

of  coal  or  other  rock 
Basalt,  a  dark  green  rock  divided  in  columnsL 

Climatology,  a  treatise  on  climate. 

Caloric,  the  agent  which  produces  heat 

Coalesce,  to  unite  or  run  together. 

Condense,  to  make  more  dense. 

Clouds,  floating  particles  of  water  or  other  matter. 

Congeal,  to  freeze  or  harden. 

Crystalization,  the  act  of  forming  crystals. 

Concentric,  having  a  common  centre. 

Cohesion,  the  force  which  holds  the  particles  of  bodies  together. 

Corona,  a  luminous  circle  round  the  sun  or  moon. 

Cleavage  planes,  the  flat  surface  formed  by  the  cleavage  of 
rocket. 


244  GLOSSART. 

Continuity,  unbroken,  continuous  texture. 

Carboniferous,  any  bed  or  rock  containing  coal. 

Coral,  a  maritime  production  composed  of  lime,  and  the  habi- 
tation of  insects. 

Cuboidal,  in  the  form  of  a  cube :  square. 

Columnar,  having  the  form  of  columns. 

Chalcedony,  a  species  of  quartz-like  mineral. 

Calcareous  spar,  crystalized  carbonate  of  lime. 

Crater,  the  opening  of  a  volcano  through  which  its  eruptions 
take  place. 

Chlorite,  a  simple  mineral  of  a  green  color. 

Crucible,  an  earthen  or  metallic  po<»  in  which  ores  are  melted 
and  purified. 

Crenic  acid,  an  acid  found  in  peat  and  humus  soils. 

Calcareous,  limy,  composed  mostly  of  lime. 

Caustic,  corrosive,  biting,  burning. 

Calcine,  to  burn. 

Cuticle,  the  outside  bark  or  skin. 

Capillarity,  the  property  of  absorbing  by  capillary  attraction. 

Carbonate  of  potash,  pearlash. 

Chlorine,  a  simple  substance. 

Calorific,  producing  heat. 

Capacity  for  caloric,  power  of  containing  latent  heat. 

Combustion,  the  act  of  burning. 

Conductors,  substances  which  conduct  caloric  or  electricity. 

Carbon,  charcoal. 

Clarify,  to  make  clear  or  clqan. 

Carbonic  acid,  a  compound  of  carbon  and  oxygen. 

Complex,  having  many  component  parts. 

Coniferous,  bearing  seeds  in  cones,  like  the  pine. 

Carmine,  a  coloring  matter  of  a  pink  color. 

Casiene,  an  organic  ekment  the  basis  of  cheese. 

Caramel,  a  substance  produced  by  heating  sugar. 

Carburetted  hydrogen,  a  gas  composed  of  carbon  and  hydrogen. 


GLOSSARY.  246 

Carbonic  oxide,  a  gas  composed  of  carbon  and  oxygen. 

Corrosive,  having-  the  property  of  corroding  and  destroying. 

Ce/htlar,  composed  of  small  cells. 

Cryptogamous,  having  flowers  too  minute  to  be  seen  with  the 
naked  eye. 

Cotyledon,  a  seed  lobe. 

Carnivora,  the  class  of  animals  which  live  on  flesh. 

Cruciform,  having  the  form  of  a  cross. 

Calyx,  a  cup,  the  bottom  part  of  a  flower. 

Corolla,  the  closed  leaves  of  a  flower. 

Crude,  raw,  immature. 

Cordate,  heart  shaped. 

ChlorophyUe,  the  green  coloring  matter  of  plants. 

Cambium,  the  descending  sap  which  forms  wood. 

Centripetal,  tending  towards  the  centre. 

Cereals,  the  white  straw  grains,  as  wheat  and  rye. 

Chrysolite,  a  simple  mineral,  of  gold  color. 

Centrifugal,  tending  to  recede  from  the  centre. 

Corymb,  a  cluster  of  flowers  whose  stalks  spring  from  different 
heights,  and  form  a  flat  top. 

Cyme,  a  cluster  of  flowers  whose  stalks  rise  from  a  common 
centre,  and  afterwards  subdivide  irregularly. 

Contagion,  an  infectious  or  pestilential  disease  which  is  com- 
municated by  contact  or  through  the  atmosphere,  from  one 
animal  or  plant  to  another. 

Denude,  to  make  naked  or  bare. 

Dunes,  hills  of  blown  sand. 

Disintegrate,  to  separate  into  integral  parts. 

Ductile,  capable  of  being  drawn  into  wire. 

Dilute,  to  make  thin  or  reduce  in  strength. 

Deciduous,  falling  off  in  the  usual  season :  not  persistent. 

Dissemination,  the  act  of  sowing  or  scattering. 

Dilate,  to  expand,  extend,  enlarge. 

Digestion,  the  act  of  assimilating  food  to  the  body. 
*21 


546  GLOSSARY. 

Digitate,  divided  like  the  fingers. 

Dip,  the  inclination  of  a  stratum  of  rock  from  the  horizon. 

Dyke,  a  mass  of  rock  which  appears  to  have  been  injected  into 

the  fissures  of  other  rocks. 
Drift,  masses  of  sand  or  other  matters  driven  together  by 

water. 

Deleterious,  injurious,  noxious. 

Duramen,  the  inside,  brown  heart  of  wood  of  forest  trees. 
Decompose,  to  separate  into  parts  or  elements. 
Data,  known  or  admitted  facts  or  principles. 
Deutoxide,  a  chemical  compound  containing  two  proportions  of 

oxygen. 

Daguerreotype,  a  process  of  taking  pictures  by  means  of  light. 
Dynamical,  pertaining  to  strength  or  power. 
Deliquiesce,  to  dissolve  gradually  by  attracting  and  absorbing 

moisture  from  the  air. 
Distillation,   separating  essential  oils   or  alcohol   from   other 

matters,  by  means  of  heat, 
Diurnal,  daily,  occurring  daily. 

Disinfecting,  purifying  and  preventing  contagion  or  infection. 
Extant,  now  in  use. 
Extirpate,  to  destroy  or  eradicate. 
Excavate,  to  dig  or  wear  out  a  hollow  or  cavity, 
Excrements,  matters  voided  or  excreted  by  animals. 
Endogens,  plants  which  grow  from  the  inside. 
Electricity,  a  principle  in  nature  usually  called  lightning. 
Elasticity,  power  of  resuming  form  after  compression. 
Elective  affinity,  that  affinity  which  causes  an  acid  or  alkali  to 

abandon  one  with  which  it  is  already  united,  and  unite  with 

another. 
Ether,   a  subtil  matter  which   is  much  lighter  than  air,  and 

supposed  to  exist  beyond  the  limits  of  the  atmosphere. 
Emit,  to  send  off,  give  out  or  discharge. 
Expansion,  the  act  of  enlarging  or  increasing  in  bulk. 


GLOSSARY.  247 

Equivalent  number,  the  particular  quantity  of  any  substance 

required  to  combine  with  or  saturate  another  substance. 
Emanate,  to  issue  or  flow  from. 
Electric,  a  substance  capable  of  giving  off  electricity. 
Electrical  repulsion,  that  property  which  causes  bodies  in  the 

same   state  of  electrical  excitement  to  separate:    opposite 

attraction. 

Exude,  to  run  out  or  issue  from. 
Equilibrium,  balance  of  forces  or  properties. 
Epiphytes,  plants  growing-  upon  the  trunk  and  branches  of 

other  plants  and  deriving  nourishment  mostly  from  the  air. 
Epidermis  outside  skin  or  bark. 
Excrete,  to  eject  or  throw  out. 
Embryo,  the  germ  of  a  plant  or  animal. 
Elliptical,  an  oval  figure  with  pointed  ends. 
Exogens,  plants  which  grow  by  layers  on  the  outside. 
Exhalation,  breathing  out,  giving  off,  emitting. 
Evolution,  emission,  giving  off,  discharging. 
Element,  a  component  part,  first  principle. 
Equator,  an  imaginary  line  dividing  the  earth  into  two  halves ; 

the  equinoctial  line. 
Effloresce,  to  become  a  dry  powder. 
Eremacausis,  slow  combustion  or  decay. 
Evaporation,  becoming  volatile,  flying  off  with  the  air,  drying 

up. 

Escarpment,  a  steep  ledge  of  rocks. 
Eurite,  a  white  mineral. 
Eject,  to  throw  out,  discharge. 
Effervesce,  to  foam,  bubble,  ferment. 
Fasicle,  a  small  bundle. 

Flora,  the  goddess  of  flowers,  a  flower  or  book  of  flowers. 
Functional,  pertaining  to  the  office  or  use  of  a  part  of  any 

organism. 
Filament,  the  slender,  thread-like  part  of  the  stamen. 


548  GLOSS  Any. 

Fibrils,  minute  branches  of  roots. 

Fibrous,  composed  of  fibres. 

Fusiform,  spindle- shaped,  tapering. 

Fasciculated,  collected  in  heads  or  bundles. 

Fundamental,  original,  elementary,  first  principle. 

Fructification,  the  flower  and  fruit  with  their  parts,  the  act  of 
making  fruitful. 

FAHRENHEIT,  the  inventor  of  the  thermometer  which  bears 
that  name. 

Fault,  a  cleft  or  fissure  in  a  rock. 

Fossil,  the  remains  of  animals  and  plants  found  buried  in  the 
earth. 

Formation,  a  group  of  any  kind  of  rocks  referred  to  a  common 
origin  or  period. 

Fossiliferous,  containing  fossils. 

Fissure,  a  crack  or  cleft. 

Fuse,  to  melt,  become  fluid  from  heat. 

Faggot,  a  bundle  of  sticks  or  brush. 

Friable,  easily  crumbled  or  pulverized. 

Fertilizers,  substances  used  to  enrich  the  soil. 

Focus,  the  point  at  which  rays  of  light  or  heat  meet 

Fluor  spar,  a  mineral  compound  of  lime  and  fluoric  acid. 

Fibre,  a  slender,  thread-like  organ  or  substance. 

Fumes,  vapor,  gas  or  smoke. 

Freezing  point,  this  is  placed  at  32°  Fahrenheit. 

Feldspar,  a  simple  mineral  which  constitutes  a  principal  ingre- 
dient of  most  rocks. 

Fire  damp,  light  carburetted  hydrogen. 

Fibrine,  the  colorless  part  of  the  blood  which  when  separated 
from  it  becomes  jelly-like. 

Geology,  the  science  of  the  earth's  structure,  (fee. 

Graphite,  black  lead. 

Galvanism,  a  species  or  modification  of  electricity. 

Glutinous,  sticky,  visced,  having  the  characters  of  glue. 


GLOSSARY.  249 

Generate,  to  produce  or  create. 

Gelatine,  a  proximate  principle  in  plants  and  the  bodies  of  ani- 
mals, usually  called  jelly. 

Guano,  a  species  of  manure  composed  mostly  of  the  excre- 
ments of  sea  fowl. 

Granite,  an  unstratified  primary  rock. 

Greenstone,  a  variety  of  trap  rock  composed  of  hornblende 
and  feldspar. 

Gneiss,  a  primary  stratified  rock  composed  of  the  same  mate- 
rials as  granite. 

Garnet,  a  simple  crystalized  mineral,  generally  of  a  deep  red 
color. 

Gypsum,  plaster  of  paris,  sulphate  of  lime. 

Graphic  granite,  is  a  species  of  granite  in  which  the  quartz  is 
so  arranged  as  to  give  the  surface  the  appearance  of  having 
letters. 

Gorge,  a  deep  fissure  or  valley. 

Gyration,  turning  in  a  circular  or  spiral  direction. 

Glossology,  the  application  of  names  to  the  various  organs  of 
plants. 

Granulated,  consisting  of  small  grains,  granules,  or  masses. 

Genus,  the  subdivision  of  an  order. 

Gland,  an  organ  in  animals  and  vegetables  which  performs  the 
function  of  secreting  a  fluid. 

Germination,  the  unfolding  of  the  seed  and  development  of 
the  embryo. 

Geine,  a  substance  obtained  from  decayed  wood,  and  contain- 
ing an  acid  called  the  geic  acid. 

Glanular,  consisting  of  grains. 

Grayivacke,  an  ancient  fossiliferous  rock,  generally  of  a  gray 
color. 

Gravity,  weight :  specific  gravity,  the  weight  of  a  particular 
body  compared  with  some  standard. 

Gas,  an  elastic  fluid,  or  air. 


250  GLOSSARY. 

Gelatinous,  containing  gelatine. 

Homogeneous,  of  the  same  nature,  consisting  of  similar  parts, 
all  alike  in  structure. 

Hornblende,  a  simple  mineral  of  dark  green  or  black  color. 

Humid,  moist,  wet 

Harmattan,  a  dry  easterly  wind  in  Africa. 

Haziness,  foggy,  smoky,  misty. 

Horizon,  the  line  where  the  earth  and  sky  appear  to  meet. 

Hydrogen,  a  gas,  the  lightest  of  all  known  bodies. 

Hues,  tints,  colors. 

Hurricane,  a  violent  storm  or  tempest. 

Halo,  a  circle  appearing  around  the  sun,  moon,  or  stars. 

Hypothesis,  a  supposition  or  theory  assumed  but  not  proved : 
used  for  the  purpose  of  argument. 

Hexagonal,  six  sided :  having  six  sides  and  six  angles. 

Hydracid,  an  acid  formed  by  the  union  of  a  substance  with 
hydrogen  without  oxygen. 

Hematoxyline,  the  coloring  principle  of  logwood. 

Hydrate,  a  compound  containing  water. 

Humic  acid,  an  acid  obtained  from  humus. 

Herbaceous,  herb-like,  not  woody. 

Herbarium,  a  book  in  which  dried  plants  are  preserved. 

Imbibe,  to  take  in,  absorb. 

Irrigation,  the  act  of  watering,  moistening. 

Incineration,  the  act  of  reducing  to  ashes. 

Intersect,  to  meet  and  cross  each  other. 

Isoincric,  bodies  which  differ  in  properties  but  agree  in  com- 
position. 

Inter  stratified,  stratified  between  or  among  other  bodies. 

Infusible,  that  cannot  be  fused  or  melted. 

Incas,  inhabitants  of  Peru  and  some  other  parts  of  S.  America. 

Inf. ate,  to  blow  up,  fill  with  wind. 

Isothermal  lines,  lines  which  pass  through  points  on  the  sur- 
face of  the  earth  at  which  the  mean  temperature  is  equal. 


GLOSS  ARV.  251 

laochlmencd  lines,  lines  passing  through  points  on  the  earth  at 

which  the  mean  temperature  of  the  winter  is  equal. 
Intertropical,  between  the  tropics. 
Jf/ nis  fatuus,  Jack  0' Lantern. 
Inverted,  turned  upside  down. 
Igneous,  rocks,  such  as  have  been  melted  by  fire  or  volcanic 

heat 

Infusoria,  animalcules  too  minute  to  be  seen  by  the  naked  eye. 
Interlace,  to  tangle  or  lace  together. 
Inflorescence,  the  manner  in  which  flowers  are  connected  with 

the  plants. 

Indigenous,  native  of,  or  growing  wild  in  a  country. 
Joint,  the  parting  lines  in  rocks,  often  at  right  angles  with  the 

planes  of  stratification. 
Kaolin,  a  species  of  potter's  clay. 
Lignite,  wood  converted  into  a  kind  of  coal. 
Lava,  the  melted  stone  which  is  thrown  out  of  volcanoes. 
Lichens,  cryptogamic  plants,  of  a  crusty  texture,  growing  on 

rocks  and  the  trunks  and  branches  of  trees. 
Lenticular,  having  the  form  of  a  lens. 
Longevity,  length  of  life. 
Laticiferous,  the  system  of  vessels  in  the  bark  of  plants,  which 

circulates  their  fluids. 
Latex,  the  fluid  formed  from  the  sap,  and  which  nourishes  all 

parts  of  plants. 

Lanceolate,- in  the  form  of  a  lancet 

Lyrate,  pinnatified  wiih  a. large  roundish  leaflet  at  the  end. 
Linear,  long  and  narrow  with  parallel  sides,  as  in  the  leaves  of 

the  grasses. 

Leguminous,  having  legumes  or  pods,  as  the  bean  and  pea. 
Liber,  the  inner  bark  of  plants. 
Lamina,  layers,  thin  plates  or  leaves. 
Longitude,  the  distance  of  places  on  the  globe  in  an  east  and 

west  direction. 


252  GLOSSARY. 

Latitude,  distance  or  degrees  north  and  south. 

Laminated,  in  lamina,  layers  or  leaves. 

Lunar,  pertaining  to  the  moon. 

Limpid,  pure,  clear,  transparent:  thin  when  used  in  reference 
to  some  fluids. 

Marine,  pertaining  to  the  sea. 

Microscopic,  objects  which  are  too  small  to  be  seen  without  the 
aid  of  the  microscope. 

Macerate,  to  soak,  dissolve. 

Maximum,  the  greatest  number  or  quantity  attainable  in  any 
given  case. 

Magnetism,  the  power  or  force  which  causes  the  magnetic 
needle  to  point  north  and  south. 

Molecules,  the  ultimate  or  minute  particles  of  matter. 

Mirror,  a  looking-glass. 

Mercury,  quicksilver. 

Mucilage,  a  slimy  fluid,  one  of  the  proximate  elements  of  plants. 

Mordant,  any  substance  used  by  dyers  to  set  colors,  or  render 
them  permanent. 

Must,  the  juice  of  grapes  which  has  not  fermented,  new  wine. 

Metamorphosis,  change,  transformation. 

Meteorology,  the  branch  of  science  which  treats  of  changes  of 
weather  and  other  atmospheric  phenomena. 

Meteor,  any  appearance  or  phenomena  observed  in  the  atmos- 
phere. 

Mean  temperature,  that  point  which  lies  midway  between  the 
two  extremes  of  heat  and  cold. 

Mist,  fog,  vapor. 

Maritime,  relating  or  pertaining  to  the  sea. 

Monsoon,  a  periodical  wind  which  blows  six  months  in  one  di- 
rection, and  then  changes  and  blows  six  months  in  the  op- 
posite direction. 

Moor,  a  marsh  or  fen,  or  land  overgrown  with  heath  and  other 
shrubs. 


GLOSSARY.  253 

Mirage,  an  optical  illusion  described  in  meteorology. 
Mineral,  in  common  language,  the  metals  and  rocks. 
Metalloid,  a  name  applied  to  some  of  the  metallic  bases  of  the 

earths. 
Mica,  a  rock  which  is  divided  or  laminated  in  its  shining  scales, 

and  of  various  colors. 
Metamorphic,  rocks  which  have  been  altered  by  the  action  of 

fire. 
Muriate  of  magnesia,, &  salt  formed  by  the  union  of  magnesia 

with  muriatic  or  hydrochloric  acid. 
Mammalia,   vertebrated   animals,   which   have   warm   blood, 

breathe  by  means  of  lungs,  bring  forth  living  young  and 

nourish  them  by  milk. 
Membrane,  a  thin  delicate  skin. 
Midrib,  the  main  or  middle  rib  of  a  leaf,  running  from  the  base 

to  the  point 

Medullary,  pertaining  to  the  pith  or  marrow. 
Morphology,  that  part  of  botany  which  treats  of  the  formation 

and  metamorphosis  of  organs. 
Malleable,  a  metal  which  can  be  hammered  and  drawn  out 

into  various  forms  by  the  hammer,  as  iron. 
Nutrient,  nourishing,  or  pertaining  to  nutrition. 
Noxious,  hurtful,  injurious,  unwholesome. 
Nomenclature,  a  system  of  naming  or  applying  technical  terms 

in  any  art  or  science. 
Nutrition,  the  act  or  process  of  supplying  the  proper  matter 

for  the  growth  of  animals  and  plants. 
Nitric  acid,  aquafortis. 
Nitrate  of  potash,  salt  petre. 
Node,  a  knot  or  protuberance. 
Nocturnal,  nightly,  occurring  every  night 
Nickel,  a  grayish  white  brittle  metal. 
Nodular,  having  nodes  or  knots. 
Napiform,  resembling  a  turnip  in  form, 

22 


254  GLOSSARY. 

Ovary,  a  name  in  botany  given  to  the  outer  covering  of  the 

germ. 
Ovules,  little  eggs,  the  rudiments  of  seeds  which  the  germ 

contains  before  its  fertilization. 
Orbicular,  round,  circular. 

Organography,  a  description  of  the  organs  of  plants. 
Organic,  composed  of  various  parts  or  organs  which  perform 

separate  offices. 

Oxidize,  to  become  rusty  or  combine  with  oxygen. 
Observatory,  a  place  or  building  for  making  observations  on 

the  heavenly  bodies. 

Opake,  not  transparent,  not  pervious  to  rays  of  light 
Optical,  pertaining  the  eye,  to  vision,  or  the  science  of  optics. 
Orbit,  in  astronomy,  the  path  of  a  comet  or  planet. 
Outcrop,  the  naked  ends  of  strata  of  rock  which  protrude 

above  the  surface  of  the  earth,  as  on  the  side  of  a  hill. 
Oolite,  a  limestone  composed  of  rounded  particles  like  the  eggs 

of  fish. 

Organic  remains,  the  fossil  remains  of  plants  and  animals. 
Olivme,  an  olive  colored  simple  mineral  often  found  in  grains 

and  crystals  in  basalt  and  lava, 

Oxide,  a  chemical  compound  of  metals  with  oxygen,  &c. 
Oxygen,  a  gas. 

Oxalute,  a  salt  composed  of  oxalic  acid  and  a  base. 
Oxalic  acid,  an  acid  obtained  from  sorrel. 
Ordure,  excrement,  faeces,  manure. 

Permeate,  to  penetrate  or  pass  through  the  pores  of  a  body. 
Phospkuretted  Hydrogen,  a  compound  of  phosphorus  and  hy- 
drogen. 

Poudrette,  a  manure  prepared  from  ordure. 
Philosopher's  stone,  an  imaginary  mineral  sought  by  the  alchy- 

mists,  which  was  supposed  to  be  capable  by  mixture  with 
the  baser  metals  of  transmuting  them  into  gold. 
Proximate,  near;  "proximate  elements,"  those  elements   of 


GLOSSARY.  255 

plants,  such  as  starch,  gum,  &c.,  which  are  composed  of  the 

immediate  elements,  viz :  the  gases  and  mineral  matters. 
Protoxide,  a  compound  containing  one  proportion  of  oxygen. 
Photographic,  pertaining  to  light;  photographic  pictures  are 

taken  by  light. 
Phosphorescence,  a  peculiar  luminous  matter  without  fire  or 

combustion,  as  the  light  given  out  by  phosphorus,  decayed 

wood,  putrifying  flesh,  <fec. 
Parabola,  a  conic  section  arising  from  cutting  a  cone  by  a 

plane  parallel  to  one  of  its  sides. 
Prism,  in  optics,  a  triangular  glass  instrument  for  separating 

the  rays  of  light. 
Polarity,  that  property  which  causes  one  end  of  a  body  to 

repel  and  the  other  to  attract,  as  in  bodies  magnetized  or 

electrified;  pointing  towards  the  poles. 
Putrefaction,  decomposition  or  decay  of  organic  bodies. 
Pungent,  biting,  hot,  sharp. 
Ponderable,  possessing  weight. 
Precipitate,  to  throw  down  or  separate. 
Phosphates,  compounds  containing  phosphorus. 
Parallelism,,  the  state  or  quality  of  being  parallel. 
Petrify,  to  become  stone. 
Pebble,  a  small  stone. 
Plutonic,  pertaining  to  subterranean  heat 
Porphyry,  an  unstratified  igneous  rock. 
Pegmatite,  primitive  granite  rock, 
Pumice  stone,  a  species  of  lava. 
Plumbago,  black  lead,  graphite. 
Pulverulent,  consisting  of  fine  dust  or  powder. 
Phenomena,  an  appearance. 
Phase,  an  appearance,  exhibited  by  the  illumination  of  the 

moon  or  other  planets. 
Polar  elevation,  height  of  latitude,  or  approach  towards  the 

poles. 


256  GLOSSARY. 

Pestilential,  infectious,  spreading  pestilence.  . 

Phosphorus,  a  simple  combustible  body  of  a  yellowish  color, 

and  the  consistence  of  beeswax. 
Physical,  pertaining*  to  matter  or  physics. 
Parhelia,  mock  suns,  or  luminous  spots  near  the  sun. 
Pistil,   the  central  organ  of  most   plants   consisting   of  the 

stigma,  style  and  germ. 
Perianth,  a  sort  of  calyx,  the  floral  envelops,  consisting  of  the 

calyx  and  corolla,  which  are  placed  around  the  pistils  and 

stamens. 
Pollen,  the  dust  contained  within  the  anthers  of  flowers,  and 

necessary  to  fructification. 

Placenta,  a  part  of  the  ovary  to  which  the  ovules  are  attached. 
Pericarp,  the  seed  covering. 

Parasite,  a  plant  or  animal  which  grows  on  another. 
Perennial,  lasting  more  than  two  years,  evergreen. 
Phenogamia,  plants  which  bear  visible  flowers. 
Petal,  a,  flower  leaf  which  is  part  of  the  corolla. 
Plumule,  the  ascending  part  of  a  germinating  plant. 
Perforate,  to  make  a  hole,  having  holes,  to  pierce. 
Parenchyma,  the  principal  and  proper  substance  of  any  organ 

in  a  plant  or  animal. 

Pervious,  porous,  or  capable  of  being  penetrated. 
Pellicle,  a  thin  skin,  film  or  crust. 
Pyrogen,  the  matter  or  generator  of  electricity. 
Porcelain,  a  fine  kind  of  earthen  ware. 
Peat,  decayed  and  decaying  vegetables,  usually  buried  below 

the  surface  of  the  ground. 

Peduncle,  the  stem  which  bears  the  flower  and  fruit. 
Panicle,  a  loose,  irregular  bunch  of  flowers,  as  in  the  oat 
Propagate,  to  produce,  or  multiply  by  shoots,  &c. 
Physiology,  the  science  which  explains  the  laws  o£  life  and 
"the  uses  and  offices  of  all  the  various  organs  of  plants  and 

animals. 


GLOSSARY.  257 

Ptdpt  the  soft  juicy  part  of  fruits  and  berries. 

Quartz,  a  simple  mineral  composed  of  silex  or  flint 

Quartzose,  containing  quartz. 

Quiescent,  in  a  state  of  quietude  or  repose. 

Quadruple,  four  times,  four  fold. 

Radiate,  to  shine,  to  proceed  in  direct  lines  from  a  point,  like 

rays  of  light  or  heat. 
Repulsion,  the  act  of  repelling  or  driving  off,  as  in  bodies  in 

the  same  electrical  state :  opposed  to  attraction. 
Rarity,  the  opposite  of  density,  thin,  light. 
Refrangibility,  capable  of  being  refracted. 
Respire,  to  breath. 

Residual,  remaining  after  a  part  is  taken,  sediment  which  sub- 
sides from  a  watery,  mixture. 

Reagent,  a  substance  employed  to  precipitate  another  from  solu- 
tion, or  to  detect  the  presence  of  some  other  substance. 
Rape,  a  plant  of  the  genus  brassica,  allied  to  the  cabbage. 
Ramify,  to  branch  off,  divide. 
Radiation,  the  act  of  radiating,  throwing  off  rays. 
Refrigerating,  producing  cold. 
Reverberate,  to  return,  rebound,  resound,  re-echo. 
Rays  of  light,  the  brilliant  luminous  lines  which  proceed  or 

radiate  from  a  luminous  body. 
Rarify,  to  make  less  dense,  to  make  thin  or  light. 
Rarifaction,  the  process  of  ratifying,  making  more  porous  by 

expansion. 
Refraction,  the  act  of  bending  or  breaking,  diviating  from  a 

direct  course,  as  in  rays  of  light 
Receptacle,  the  end  of  the  flower  stalk  to  which  the  organs  of 

fructification  are  usually  attached. 
Ramous,  branching,  having  lateral  divisions. 
Ramification,  branching,  minute  division. 
Ravine,  a  deep  hollow  or  valley  worn  out  by  water. 
22* 


258  GLOSSARY. 

Ruby,  a  precious  stone,  a  simple  mineral  of  a  carmine  red  color. 

Rachis,  the  common  stalk  to  which  florets  and  spikelets  are  at- 
tached, and  in  the  grasses  and  wheat. 

Raceme,  a  cluster,  that  variety  of  inflorescence  in  which  the 
flowers  are  arranged  by  simple  pedicels  on  the  sides  of  a 
common  peduncle,  as  the  currant. 

Respiration,  breathing,  or  the  act  of  absorbing  or  inhaling,  and 
exhaling  carbonic  acid  and  oxygen. 

Rosacea,  an  order  of  plants,  including  the  rose  tribe. 

Radicle,  the  descending  part  of  a  germinating  plant,  a  small 
root. 

Rudimental,  consisting  of  the  first  principles,  or  simple  elemen- 
tary parts. 

Reniform,  kidney  shaped. 

Silicate,  a  salt  containing  silica  united  to  a  base. 

Silecious,  containing  silex. 

STERCOLOGY,  the  science  of  manuring,  enriching,  or  improving 
the  soil. 

Smoulder,  to  burn  and  smoke  without  vent. 

Sewer,  a  drain  to  convey  off  water  underground. 

Sulphate  of  iron,  green  vitriol,  copperas. 

Spurry,  a  plant  of  the  genus  spergula,  allied  to  duckweed  and 
tares. 

Spiral,  in  the  form  of  a  screw,  gyratory  like  the  thread  of  a 
screw. 

Subordinate,  of  minor  importance,  a  secondary  or  inferior  part. 

Synthesis,  the  act  of  combining,  contrary  to  analysis. 

Spectrum,  a  visible  image  continuing  after  the  eyes  are  closed: 
the  seven  primary  colors  constitute  the  solar  spectrum. 

Statical,  in  a  state  of  rest,  the  branch  of  mechanics  which 
treats  of  bodies  at  rest. 

Sterile,  barren,  unproductive. 

Solvent,  a  substance  or  fluid  which  dissolves  other  substances. 


GLOSSARY.  259 

Safety  lamp,  a  lamp  surrounded  by  wire  gauze,  invented  by 
Dr.  Davy  to  prevent  explosions  from  the  ignition  of  gas  in 
coal  mines. 

Solar,  pertaining  to  the  sun. 

Sublimated,  brought  into  a  state  of  vapor  by  heat. 

Stamen,  a  slender  threadlike  organ  in  the  centre  of  flowers. 

Summit,  the  apex  or  top. 

Stigma,  the  summit  or  top  of  the  pistil. 

Style,  the  part  of  the  pistil  between  the  stigma  and  germ. 

Stomata,  mouths,  or  orifices. 

Spongioles,  the  minute  spongy  suckers  or  extremities  of  roots. 

Spores,  the  seeds  of  cryptogaraous  plants,  bodies  analagous  to 
the  pollen  grains  of  flowering  plants. 

Sepal,  a  leaf  of  the  calyx. 

Sagittate,  arrow  form. 

Segment,  a  part  or  principal  division  of  a  leaf,  calyx,  or  corolla. 

Stellate,  star  form. 

Succulent,  juicy. 

Shale,  a  solid  form  of  clay,  which  usually  divides  into  lamina. 

Saccharine,  sweet,  containing  sugar. 

Spadix,  an  elongated  receptacle  of  flowers,  commonly  proceed- 
ing from  a  spathe. 

Scoria,  volcanic  cinders. 

Silicon,  the  substance  which  combined  with  oxygen  constitutes 
silicic  acid  or  flint 

Sapphire,  a  hard  mineral,  consisting  of  crystalized  alumina:  it 
is  of  various  colors ;  the  Hue  being  generally  called  the  sap- 
phire ;  the  red,  the  oriental  ruby ;  the  yellow,  the  oriental 
topaz. 

Saline,  salt,  containing  some  salt. 

Sodium,  the  metallic  base  of  soda. 

Steatite,  soapstone,  a  hydrated  silicate  of  magnesia  and  alumina. 

Snow-line,  the  lowest  point  on  mountains  at  which  there  is  per- 
petual snow. 


260  GLOSSARY. 

Subterranean,  underground,  below  the  earth's  surface. 

Submerge,  to  plunge  under  water,  to  overflow. 

Strata,  layers  of  rock. 

Spherule,  a  little  sphere,  or  ball. 

Simoon,  a  hot  suffocating  wind,  that  blows  occasionally  in  Af- 
rica and  South  America. 

Sirocco,  a  pernicious  wind  that  blows  from  the  south-east  in 
Italy. 

Salubrious,  healthful,  favorable  to  health. 

Supernatur al,  miraculous,  out  of  the  usual  course  of  nature. 

Solar  spectrum,  the  seven  primary  colors  as  seen  in  the  rain- 
bow. 

Stratified,  arranged  in  strata  or  layers. 

Silurian,  a  series  of  rocks  forming  the  upper  subdivision  of 
the  sedimentary  strata  found  below  the  old  red  sandstone, 
and  formerly  designated  the  graywacke  series. 

Scape,  a  stalk  which  springs  from  the  root,  and  supports 
flowers  and  fruit,  but  no  leaves. 

Saturate,  to  fill  with  a  fluid,  absorb,  soak. 

Sedimentary  rocks,  are  those  which  have  been  formed  by 
their  materials  having  been  thrown  down  from  a  state  of 
suspension  or  solution  in  water. 

Syenite,  a  kind  of  granite  so  called  because  it  was  formerly 
brought  from  Syene  in  Egypt. 

Serpentine,  a  rock  usually  unstratified,  containing  much  mag- 
nesia, and  often  speckled  of  various  colors,  like  a  serpent's 
back. 

Sculpture,  the  art  of  carving  wood  or  stone  into  the  images  of 
men  or  animals. 

Stucco,  a  fine  white  plaster,  to  plaster  with  stucco. 

Stalactite,  a  variety  of  carbonate  of  lime  in  the  form  of  icicles, 
produced  by  the  filtration  of  water  containing  lime  in  solu- 
tion, from  the  crevices  of  rocks  in  the  roofs  of  caverns. 

Stalagmites,  are  similar  to  stalactites,  but  formed  by  the  drop- 


GLOSSARY. 


261 


ping  of  water  on  the  floors  of  caverns,  and  having  their 
points  upwards. 

Twilight,  the  light  at  the  close  of  day  after  sunset  and  before 
dark. 

Tortuous,  crooked,  convoluted. 

Tertiary,  a  series  of  sedimentary  rocks,  lying  above  the  pri- 
mary and  secondary,  and  having  characters  which  distin- 
guish them  from  these  two  classes. 

Trachyte,  a  variety  of  lava  essentially  composed  of  greenstone : 
it  frequently  contains  detatched  crystals  of  feldspar,  and 
sometimes  hornblende  and  augite. 

Titaniferous,  an  iron  ore  containing  titanium. 

Talc,  a  species  of  magnesian  earth,  consisting  of  smooth  shining 
lamina,  translucent  or  transparent.  * 

Transparent,  admitting  rays  of  light  to  pass  through. 

Transverse,  crosswise,  across. 

Terrestrial,  belonging  to,  or  pertaining  to  the  earth. 

Tillage,  includes  all  mechanical  operations  on  the  soil. 

Tropical,  belonging  to  the  tropics. 

Torrid  zone,  the  hot  country  included  between  the  Tropic  of 
Cancer,  and  the  Tropic  of  Capricorn. 

Tornado,  a  high  wind,  a  whirlwind. 

Theory,  an  exposition  of  the  principles  of  any  science;  the 
science  without  the  art  or  practice. 

Tissue,  connection  or  organization,  the  proper  substance  of  an 
organ. 

Terminal,  situated  at  the  end. 

Thyrse,  a  loose  irregular  bunch  of  flowers. 

Tenacity,  toughness,  having  strong  cohesion, 

Tap  root,  the  main  root,  the  axis. 

Tuber,  a  fleshy  knob  or  tumor  on  a  rcot. 

Trifolium,  the  genus  of  plants  to  which  clover  belongs. 

Ternate,  leaves  which  are  arranged  in  threes  are  called  ter- 
nate. 


262  GLOSSARY. 

Transmit,  to  permit  to  pass,  to  convey  through. 

Tint,  shade,  hue,  color. 

Transition,  rocks  which  appear  to  have  been  formed  while  the 
earth  was  in  a  state  of  transition,  from  a  state  of  desolation 
to  a  habitable  condition.  They  have  a  texture  partly  me- 
chanical and  partly  chemical. 

Urea,  the  principal  element,  next  to  water,  in  the  composition 
of  the  urine. 

Vhnic  acid,  a  substance  formed  by  the  action  of  acids  on 
sugar. 

Unconsolidated,  soft,  not  consolidated. 

Umbel,  a  kind  of  infloresence  in  which  the  flower  stalks  diverge 
from  one  centre,  as  the  wild  parsnep. 

Volcano,  a  burning  mountain. 

Vision,  sight,  the  act  of  seeing. 

Veins,  cracks  or  fissures  in  rocks  which  are  filled  with  sub- 
stances different  from  the  rock,  either  mineral  or  earthy. 

Volcanic,  pertaining  to  volcanoes,  produced  by  volcanoes. 

Vertical,  perpendicular,  overhead. 

Vapor,  mist,  fog,  small  particles  of  water. 

Vesicles,  small  particles  or  drops. 

Verticil,  whorled,  having  leaves  or  flowers  in  a  circle  round 
the  stem. 

Volatile,  evaporating  or  flying  off  easily. 

Vascular,  made  up  of  vessels,  or  full  of  vessels. 

Vasiform  tissue,  is  made  up  of  large  tubes. 

Venation,  the  arrangement  of  the  ribs  or  veins  in  leaves. 

Viscid,  stringy,  sticky,  slimy. 

VerticiUate,  whorled. 

Verdure,  foliage,  herbage. 

Vibrate,  to  swing  or  oscillate. 

Vacuum,  an  empty  space,  a  space  from  which  the  air  has  all 
been  removed. 

Vitality,  life,  the  vital  or  living  principle. 


GLOSSARY.  263 

Vital  functions,  those  functions  or  actions  which  arc  indispen- 
sable to  organic  life. 

Vetches,  a  liguminous  plant  allied  to  the  pea,  bean,  and  lentil 

Warping,  a  process  in  agriculture  similar  to  irrigation. 

Wealden,  a  fresh  water  group  of  rocks,  composed  of  clay,  lime 
marl,  &c. 

Zigzag,  in  a  crooked  direction,  forming  short  angles. 

Zenith,  that  point  in  the  sky  or  celestial  hemisphere  which,  is 
vertical  to  the  spectator. 

Zanthine,  a  substance  found  in  urinary  calculi 

Zeolite,  a  mineral  composed  of  silica,  alumina  and  lime. 


INDEX. 


ANALYSIS,  -                                               23 

Affinity,  chemical  28 

Affinity,  simple  28 

Affinity,  elective  -               29 

Attraction,  chemical  -  28 

Atmosphere,                  ""  *  47 

Acid,  nitric    -  50 

Aquafortis,           -  50 

Ammonia,     -  -                                                51 

Acids,  properties  of  -   •           55 

Alkalies,  properties  of  55 

Albumen,  -                                                        60 

Acids,  vegetable,       -  63 

Alkalies,  vegetable  63 

Apotheme,    -  -         64 

Alizarine,  -                                                     64 

Alluvium,      -  78 

Amygdaloid,  -                                                      84 

Appendages  of  plants,  96 

Anther,  "•  -•'         -                            99 

Albumen,      -  ".»•••                                    -       101 

Aerial  roots,  105 

Annual  roots,  -       105 

Alburnum,           -  108 

Absorption,   -  117 

Agriculture,  influence  of  on  climate  and  fall  of  rain,  133 

Aerolites,      -  149 

Aluminum,           -  -            -            -            -            158 

23 


26G  INDEX. 

Alum,                                                                                -  158 

Analysis  of  soils,  -  227 
Analysis  of  soils  to  determine  the  quantity  of  vegetable 

matter, .  228 
Analysis  of  soils  to  determine  the  quantity  of  sand  and 

clay,     -  228 

Analysis  of  soils  to  determine  the  quantity  of  water,  -  228 

Analysis  of  soils  to  determine  the  quantity  of  humic  acid,  229 

Analysis  of  soils  to  determine  the  quantity  of  ulmic  acid,  229 
Analysis  of  soils  to  determine  the  quantity  of  crenic  and 

apocrenic  acids,  229 

Analysis  of  soils  to  determine  the  quantity  of  lime/    -  230 

Analysis  of  soils  to  determine  the  quantity  of  silica,  230 
Analysis  of  soils  to  determine  the  quantity  of  oxide  of  iron,  230 
Analysis  of  soils  to  determine  the  quantity  of  different 

salts,    -  230 

Analysis  of  a  fertile  soil,                                                 -  231 

Analysis  of  a  barren  soil,  231 

Aurora  Borealis,  146 

Analysis  of  beech  and  oak  ashes,  -  207 

Ashes  of  coal,  peat,  <kc.,  as  manures,    -  208 

Analyses,  tables  of  216 

Analysis  of  wheat,     -  216 

Analysis  of  barley,  217 

Analysis  of  oats,        -  217 

Analysis  of  rye,  -  218 

Analysis  of  peat,        -                           -  218 

Analysis  of  coal  ashes,      -  219 

Analysis  of  bean  and  pea,      -  219 

Analysis  of  turnip  and  potato,       -  219 

Analysis  of  carrot  and  parsnep,                                      -  220 

Analysis  of  grass  and  clover,  220 

Analysis  of  silica  plants,                                                  -  221 

Analysis  of  lime  plants,    -  221 

Analysis  of  potash  plants,       -  222 

Analysis  of  fseces  of  horse,  222 

Analysis  of  urine  of  horse,     -  222 

Analysis  of  feces  of  cow,  223 

Analysis  of  urine  of  cow,       -  223 

Analysis  of  human  fseces,  223 

Analysis  of  human  urine,       -  22B 


INDBX.  267 

Analysis  of  guano,                 *       4  *            - . .  •       -      224 

Analysis  of  bones  of  the  ox,    .     -  J,     -                         224 

Analysis  of  coal  soot,  -       224 

Analysis  of  wool,  hair,  horns,  225 

Analysis  of  ox  blood  and  muscle,  .  -       ,     -             -       225 

B 

Bed,                 .'     -      .      -              74 

Basalt,  -         84 

Botany,    -  91 

Botany,  divisions  of   -            •     ,  *  *»-'•'<     -            -        91 

Breeze,-    -  ••           •            145 

Bridges,     >  •-        •    -     ••  •»/  ».'••    *•"*'.      -  -       239 

Biennial  roots, .     -             -             105 

Buds,                      >  -     ••  ,    if     *  ;•  *       ,..  *v           -       107 

Bole,        -  *            -            167 

Blood,  as  manure,     '*'•'         -  *            -                   192 

Bones,  as  manure,        ....  „     -..*>«]         192 


Calcium,        -  -             -       162 

Charcoal,  animal                »        *  ;    '      .    -             -             192 

Chaff  as  manure,  '    -       ;    -  -             -       197 

Charcoal  as  manure,    '  198 

Carbonate 'of  soda*  as  manure,  •  *  **         •       204 

Chloride  of  sodium,  or  'common  salt,  as  manure,    -  206 

Chloride  of  lime  and  magilesia  as  manures,     -  -       206 

Crushed  rocks,"  as  manure,  -                          •«             208 

Chalk  as  a'  manure*,   -  -                   209 

Composts,  -             212 

Comparative  value*  of  manures,  table  of          -            -       215 

Chemistry,            -       *     -       '  -      +'• ••   »             -               23 

Capillarity,    -          '  4;    -.^J;  *  *     -         >    *      *•    iw**     24 

Cohesfon,  v              25 

Combination,  laws* of  'f            -         80 

Caloric,    -  -               84 

Caloric,  expansive  power  of    -  34 

Caloric,  conductors  of  -               34 

Caloric,  specific,  -         35 

Caloric,  capacity  for  85 

Caloric,  radiant                   >  ,' •  «     .  •  *.          -        9$ 


268  INDEX. 

Caloric,  latent,        .  .  .  .  .  35- 

Caloric,  transmission  of  .  .  .  .36 

Cold, 37 

Carbon,  t        %    .  .  .  .  .42 

Carbonic  acid,        .....  43 

Carbonic  oxide,  .  .  .  .  .48 

Carburetted  hydrogen,       .  .  .  .  49 

Cerine,  ......         61 

Camphor,  .  .  .  .  .  61 

Caoutchouc,  •  .  .  .  .62 

Coloring  matter,    .....  64 

Chlorophylle,  ...  .64 

Colors,  adjective    .  .  .  .  .  65 

Colors,  substantive,      .  .  .  .  .65 

Carmine,  .  .  .  .  .  65 

Chlorine,          ......         65 

Compounds  derived  from  the  inorganic  elements  of  plants,  67 
Caramel,          ......         71 

Cleavage  planes,    .....  75 

Clay  slate,       ......         86 

Chalk,        ......  87 

Coal,   .  .  .  .  .  .  .87 

Coal,  varieties  and  origin  of  ...  89 

Coal  basin  in  Wales,    .  *    .  .  .89 

Class  denned,        .....  93 

Corolla,  ......        97 

Calyx,        ......  98 

Cotyledon,       ......       101 

Cellular  integument,          .  .  .  .  108 

Cambium,        ......       109 

Cryptogamous  plants,        .  .  .  .  110 

Chlorophylle,  .  .  .  .  .111 

Climate,     ......  126 

Clouds,  ......       138 

Corona,      ......  147 

Clay, 166 

D 

Divisibility,  .  .  .     •  .  25 

Density,  ......         27 

Diastase,    .  .  .  .  .  68 


INDEX. 


269 


Dip 75 

Dyke, 76 

Drift, 

Duramen,         .            .             .  .             .             .108 

Dissemination  of  seeds,      .             .  .             .             120 

Digestion,         .             .             .  .             .             .118 

Day,  longest  in  different  latitudes, 

Dry  leaves  as  manure,               .  .             .            .197 

Decayed  wood  as  manure,               .  •   '         .             197 

Draining,  its  objects     .         '    «    .  .             .             .       181 

Draining,  varieties  of                       .  .             .             182 
Dynamics,        ......       233 

Dew,          ......  136 

E 

Elasticity,              .             .             .  .             .               27 

Equivalent  number,    .             .  .             .             .31 

Electricity,             .             .             .  \.  *.*      .  ./*'.            3? 

Electricity,  negative    .             ,  »  '          .             .         38 

Electricity,  positive             .             .  .             .               38 

Electricity,  conductors  of.  .             .             .38 

Electrical  excitation,           .              .  .             .                38 

Electrical  repulsion,    .             .  »  -         » 

Electricity,  statical             .             .  V;'         •               39 

Electricity,  dynamical               .  ,*            .             .         39 

Eremacausis,         .             .             .  .             .               44 

Elementary  bodies,      .             .  .             .             .53 

Elements,  organic               .              .  .             .                57 

Elements,  proximate                .  .             .             .57 

Elements,  immediate          .             .  .             .               57 

Extractive  matter,        .             .  .             .             .64 

Escarpment,          .             .             .  ':  -Jr  '•         .               75 

Embryo,         .             .             .  v  V-     \.V          .         94 

Epidermis,             .             .         *  .  .                            96 

Embryo,          .             .             ,  .             .             .101 

Epiphytes,              .             .             .  .              .              105 

Epidermis,       .             .             .  .             .              .108 

Exhalation,             .             .             .  .             .              117 

Excrements  of  plants,  theoiy  of  ...       185 

Excrements  as  manure,      .             .  .             «             193 

Excrements,  human     .            .  ».'          .193 

24 


270  INDEX. 

Excrements  of  horned  cattle,           .            .            .  194 

Excrements  of  the  horse,          .             .             .  .194 

Excrements  of  the  hog,       .             .             .             .  195 

Excrements  of  sheep,                .              .              .  .195 

Excrements  of  birds,            .             .             .              .  195 
Epsom  salts  as  manure,             ....       205 

Earthy  manures,     .....  206 


Fire  damp,              .             .             .             .             .  49 

Fermentation,      .                      .             .             .  .69 

Fermentation,  vinous,          .  69 

Fermentation,  acetous               .             .             .  .70 

Fault, 76 

Formation,       .             .             .             .             .  .76 

Fossil,         ......  76 

Feldspar,  composition  of                        .             .  .87 

Flower,      .             .             .             .             .             .  97 

Filament,          ......         99 

Fruit,         ......  100 

Fibrils,              .             .             .             .             .  .       103 

Fusiform  roots,        .             .              .              .              .  104 

Fibrous  roots,                .              .              .              .  .104 

Faciculated  roots,                .             .             .             .  104 

Floating  roots,    .             .           .             .             .  .105 

Flowers,  terminal                .             .             .             .  118 

Flowers,  axillary           .              .              .              .  .118 

Flower,  solitary      .             .             .             .             .  119 

Forests,  their  influence  on  climate  and  the  fall  of  rain,         134 

Frost,                .             .             .    *         .             .  .136 

Frost,  cause  of                    .             .             .             .  ^137 

Fogs,                .             .             .             .             .  .    ~  138 

Fire  balls,                .....  148 

Fallowing,        .              .              .              .              .  .182 

Fallowing,  benefits  of                       .             .             .  183 

Flesh  as  manure,          .             .             .             .  .       192 

Fat  of  animals  as  manure,               .             .             .  192 

Farm-yard  manure,      .              .              .              .  .199 

Force  defined,         .....  233 

Friction,           .             .             .                          .  .237 


INDEX.  271 


Gravity,     .             .             .             .             .            .  26 

Gravity,  specific  .' 

Galvanism,              .....  39 

Gases,  properties  of     .             .            .            .  .40 

Gum,          '.,....  59 

Gluten,  .'.....         60 

Geology,   ....  .73 

Gorge,              .             .'                                      .  .76 
Granite,      .             .           J             .             . 

Greenstone,      .             .'            .             .             .  83 

Gneiss,       ......  85 

Graphite,         .... 

Genus,  defined        .....  93 

Germination,    .             .             .             .             .  .101 

Granulated  roots,   .             .             .             .             .  104 

Gale, .  .       145 

Gypsum,    .            .,           ;.            ^             ,_            .  165 

Gelatine  as  manure,     .            *.          .             .  .193 

Guano,        ......  196 

Green  manures,  .....       200 

Green  manures,  uses  of                   .                          .  200 

Glauber's  salts  as  manure,         .             ,        jf .-;  .       204 

H 

History,  natural      .             .         t    »             .             .  21 

Hydrogen,        .             .             .            .             .  .41 

Hartshorn,  spirits  of                         .             .             .  51 

Haematoxyline,              .             .             .             .  .65 

Hornblende  slate,  .....  86 

Hornblende,  basaltic,  composition  of     .             .         A  *  "      87 

Herbs, 106 

Hail,    ....         ,;  .  -      .  .  .       140 

Harmattan,             .             .         --;.  '      j.'>,          .  •  1^4 

Hurricane,        .             .             .             .             .  .145 

Halo,          .             .             .         ,  \             .             .  147 

Humus,            .             .             .             .             .  .168 

Humus,  its  composition       .             .             .             .  169 

Hair  as  manure,            .             .             .             .  .192 

Horns  as  manure,                .             .         ..'.             .  192 

Hoofs  as  manure,         .            .            *  .         *  .       192 


272  INDEX. 

I 

Isomeric  bodies,      .....  58 

India  rubber,                .             .  .             .             .62 

Indigo,       .             .             .             .  .             .               64 

Inorganic  elements  of  plants,  .             .             .65 

Iodine,        ......  66 

Idial  section  of  the  earth's  crust,  .             .             .79 

Integument,            .             .             .  .             .             101 

Inflorescence,                .             .  .             .             .118 

Inflorescence,  centripetal    .             .  .             .             119 

Inflorescence,  centrifugal          .  .             .             .119 

Isothermal  lines,     .             .             .  .             .             127 

Isochimenal  lines,          .....       127 

Ignis  fatuus,           .             .             .  .             .             147 

Iron,    .......       159 

Irrigation,                .             .             .  .             .             179 

Inclined  plane,              .             .  .             .             .234 

j 

Joint,       -  75 

K 

Kaolin,           .  -       167 

L 

Light,      -  32 

Light,  nature  of  -                                    32 

Light,  reflection  and  refraction  of  32 

Light,  origin  of                        -  -                       33 

Light,  heating  rays  of  33 

Lignine,  58 

Lava,       -  84 

Limestone,  primary  86 

Latex,      -                          ....  108 

Liber,  -       108 

Leaf,        -  -             -             111 

Leaves,  deciduous      -  111 

Leaves,  evergreen              -  111 

Leaves,  scattered       -  111 

Leaves,  alternate                            -  111 

Leaves,  opposite        -  111 


INDEX.  278 

Leaves,  verticillate  111 

Leaf,  orbicular  -       112 
Leaf,  eliptical 

Leaf,  lanceolate  -             -                          -       1 1 2 

Leaf,  cordate  -             -                            113 

Leaf,  sagittate             -  -       113 

Leaf,  reniform      -          ,  ••  113 

Leaf,  linear   -  -             -             -             -113 

Leaf,  deltoul                      -  113 

Leaf,  acerose  -       113 

Leaf,  pinnatified   -  -                           113 

Leaf,  lyrate    -  114 

Leaf,  connate        -             -  114 

Leaf,  digittate  -       114 

Leaf,  stellate  114 

Leaf,  lobed    -             -  -                                        -       114 

Leaf,  compound    -  -             115 

Leaf,  sinuate  -                                               115 

Leaf,  emarginate  •             -'                          115 

Leaf,  tubulate,  -                                  115 

Leaves,  biternate  115 

Leaves,  ternate  -                                  115 

Lightning,  140 

Lighting  rods,  -             -                                   141 

Lightning,  conditions  under  which  it  is  developed,  <fec.         142 

Land  and  sea  breezes,       -  *  .«._*         -             -             143 

Lime,             -  *  •          -                    163 

Lapping,               -             -  -             -             -             177 

Leached  ashes  as  manure,  •         ,'••»>         •             -       208 

Lime  as  manure,               -  -             -             -             209 

Lime,  mode  of  applying,  -             -             -                    210 

Lever,      -                          -  -            >.           .             234 

Latex,           -            -  -            -            -            -       117 

M 

Myricine,    ......  61 

Mordant,  ......         64 

Miea  slate,              .             .  .             .             .               86 

Mica,  composition  of    .  .             .             .             .87 

Midrib,       .             .             .  .             .           v»           111 

Meteorology,    .            .  .         '  *•*',     '  +*         .       125 

24* 


274  INDEX. 

Meteor,      ......  125 

Mirage,             .             .             .             .             .  .149 

Mists,         .             .             .             .             .             .  138 

Monsoons,         .             .             .             .             .  .145 

Manganese,              .              .              .              .              .  159 

Magnesium,      .                          .             .             .  .102 

Magnesia,                .             .             .             .             .  162 

Marl,    .......       164 

Manures,                  .              .              .              .             ".  190 

Manuring,  objects  of    .             .             .             .  .191 

Manures,  animal     .             .             .             .             .  192 

Mineral  manures,          .             .             .             .  .204 

Marl  as  manure,     .....  208 

Mechanical  philosophy,              .             .             .  .233 

Machinery,  objects  of                        .              .              .  234 

Machinery,  on  regulating  motion  of                    .  .235 

Motion,  species  of    .            .             .             .  236 

Machinery,  obstructions  to  the  action  of            .  .237 

Materials,  strength  of                       .             .             .  238 
Materials,  beams  and  columns    ....       238 

Materials,  cylinder              .             .              .             .  239 

Materials,  metals,          .             .             .             .    .  .239 

Materials,  woods     .             .             .             .             .  239 

Materials,  stone            .             .             .             .  .239 

N 

Nitrogen,         ......         45 

Napiform  roots,      .             .             .             .             .  103 

Nerves,             .             .             .             .             .  .111 

Night  soil,               .             .             .             .             .  194 

Nitrate  of  soda  as  manure,      .            .            .  .205 

0 

Oxygen,     ......  41 

Oxalic  acid,      .             .             .             .             .  .48 

Organic  bodies,  mutual  relation  of              .             .  60 
Oils,  fixed         ......         62 

Oils,  volatile            .             .             .             .             .  62 

Organic  elements,  metamorphosis  of    .             .  .         70 

Outcrop,    ......  75 

Olivine,            ,            .            .  84 


INDEX.  275 

Order  defined,      .....  93 

Ovary,  ...... 

Ovules,     ...... 

Oil  cake  as  manure,    .  .  .  .  .198 


Philosophy,  natural,         ...  .             •             .               21 

Physics,        \  *•  .$                        .              .21 

Prism,      .             f             .  ;  >'            .             .               33 

Pyrogen,        .              ,  *       •  »  r           .              .              .          39 

Phosphorus,          .          •    »•  .             .              .                66 

Phosphoric  acid,         *^  .$         .             .              .67 

Primary  rock,         .             .  .             .             .             78 

.Porphyry,       .              .  .                            .              .83 

Plants,  divisions  of           _  *'  ...                92 

Plants,  classification  of  .             •             •             .92 

Plumule,  .              ...*-.  .                94 

Pistils,            *^         .  '  .  "        ,.  *                        .97 

Perianth,  .             .'           .'  *'       .    /£          .               97 

Petals,            .            ..    '  ./      '•';-.-  *          •             .         97 

Pollen,        .           •"."          V'.  ...                99 

Placenta,          .            V  .             ."           .             .99 

Pericarp,    .            "/        ;'  *  :          .             .             .              100 

Parasitel,         .*      '  •  ?-*  ^        '..  .          .             .       105 

Perennial  roots,      .             »"  .*          ;"          .              105 

Pith,   .             .         ;    v*  .         ^,    '         .             .       107 

Parenchyma,          .             .  .  *          .             .              116 

Peduncle,         .             .  .         / ',  /         .             .119 

Panicle,      .             .             .  ;;  ,  "          ,             .             120 
Plants,  curious  phenomena  of  .         /;  . ','       >    .         .       122 

Plants,  locality  of  .             .  .           ' .  *       ^ ,  ..          123 

Plants,  diseases  of       .  .         -^,    '      ^*   ,         .       123 

Parhelia,    .             .             .  l.V  *        -^*         •             148 

Potassium,       .             .  .           ..   *        *7            .       IQI 

Peat,          .            .            .  .    .  *         .   ]         .             167 

Potter's  clay,  .             .  .          :   ,             ,*             .       167 

Pipeclay,  .             .             .  ^  .  *       ^,   "         .              167 

Peat,  composition  of    .  .             .  -'         .              .168 

Paring  and  burning,            .  .             .             .              180 

Phosphate  of  lime,       .  .           ..                          .193 


276  INDEX. 

Peat  as  manure,           .             .             .             .  .198 

Pasture,  improvement  of  the  soil  by           .             «  202 
Pasture,  temporary      .....       202 

Pasture,  permanent             ....  202 

Power  defined,             .             .             .             .  .230 

Pulley,       ......  234 

Q 

Quartz,             .             .             .             .             .  .85 

B 

Rarity,              .             .             .             .             .  .27 

Resin,         ......  61 

Rocks,  classification  of               .             .             .  .77 

Rocks,  aqueous       .....  80 

Rocks,  volcanic             ...             .             .  .80 

Rocks,  plutonic       .....  80 

Rocks,  rnetamorphic     .             .             .             .  .80 

Rock  salt,                .....  88 

Radicle,            .             .             .             ...  .94 

Rain  tables,             .             .             .             .             .  136 

Rotation,  courses  from  Colman,            .             .  »       187 

Receptacle,           .             .             .             .             .  97 

Radicle,         ......       101 

Root, 102 

Ramose  roots,             .              .             .             ,  .103 

Root,  functions  of              .             .             .             .  106 

Respiration,                 .              .              .             .  .118 

Rachis,     .                          .             .             .             .  119 

Rain,              .             .             .                           .  .135 

Rain,  its  cause,     .             .             .             .             .  125 

Rain,  its  quantity,  &c.,             .              .             .  .135 

Rainbow,               .             .              .             .             .  148 

Rainbow,  inverted      .             .             .             .  .148 

Ribbing,                .             .             .             .             .  178 

Rotation  of  crops,        .              .              .              .  .184 

Rotation,  objects  of            .             .             .             .  185 

Rotation,  courses  of  .             .             .             .  .188 


INDEX.  277 

s 

Science,  natural         .             .             .             .  .21 

Synthesis,  ..... 

Spectrum,  solar          .              .              .              .  .33 

Salts,  properties  of            .             .             .             .  56 

Salts,  acid      .             .              .              .              .  .*      56 

Salts,  neutral     '  .          *  *  *                       .             .  56 

Salts,  basic    .          *  .          "  .  "*"         .             .  .         56 

Salts,  double         .                                        .             .  56 

Salts,  deliquescent,       ,             .             .             .  .57 

Salts,  effervescent,              ....  56 

Starch,  ......         58 

Sugar,        ......  29 

Stratification,                .             .             .             .  .74 

Seam,                    „             .             .             .             .  75 

Sulphur,           .                                        .             .  .66 

Syenite,     ......  83 

Serpentine,      .         '  \             .         *    ,             .  .         84 

Slate,  talcose,      ,   ,            .             .             .             .  87 

Species  defined,          <»           .V            .             .  .94 

Stamens,               ,«•            .             .             .             .  97 

Style,              ,.'"•          .            *•      >.    5         .  .         99 

Stigma,      .             .            *        '    .             .             .  99 

Seed,                ,            4  •        £*            •             •  .101 

Spongioles,             #            »            .             .             .  103 

Shrubs,             .             .             .             .             .  .106 

Stem,  exogenous    .             .            .            .             .  107 

Sap,     .             .            .            •,  -•         .             .  .108 

Scape,      .             .         •*••;         ;  •.  %      *  ,         "-. _  •  119 

Seeds,  longevity  of     .             .             .             v  -  .122 

Snow  line,             .             ».            .              «             0  128 

Snow  lines,  table  of    .             *  *          +  •       '    « •  .       128 

Snow,       .              .              .            v           v-          •  138 

Snow  crystals,  system  of     ?.'•  •          ».v         »'*  .       139 

Simoon,    .             .            .*•. .         ;•            *4            .  145 

Sirocco,          .          ;   . ••          •*          «•           .'^  .       145 

Shooting  stars,      .              .            V            ./ •           .  149 

Silicon,           .             ./>           .             .-.*           .  .157 

Sodium,                 .              .             .              .              .  160 

Stalactites,     .             .              .             .  •            .  .165 

Stalagmites,          .  .  »*          V"  ;  *         165 


278 


INDEX. 


Spar,  gypseous,          .             .  .             .             .165 

Stitching,               .             .             .  .                           1%8 

Scarifying,      .              .              .  .              .              .178 

Soils,  physical  properties  of           .  .             .             171 

Soils,  weight  of                       .  .             .             .171 

Soils,  state  of  division  of                .  .             .             171 

Soils,  firmness  and  adhesiveness  of  .              .              .172 

Soils,  power  of  imbibing  water       .  .              .              172 

Soils,  power  of  containing  water  .             .              .172 

Soils,  power  of  retaining  water,      .  .              .              173 

Soils,  capillary  power  of          .  .             .             .173 

Soils,  their  contractibility  on  drying,  .              .'             174 

Soils,  their  power  of  absorbing  gaseous  matters,  .       174 

Soils,  their  power  of  absorbing  heat,  .             .              174 

Soils,  their  power  of  retaining  heat,  .             .             .175 

Soils,  their  power  of  radiating  heat,  .              .              175 

Soils,  their  ultimate  uses  to  plants,  .             .             .176 

Subsoil  ploughing,              .              .  .              .              178 

Stercology,     .              .              .  .              .              .190 

Skins  of  animals  as  manure,           .  .             .             192 

Straw  as  manure,       .              .  .              .             .197 

Saw  dust  as  manure,         .             .  .             .             197 

Soot  as  manure,          .              .  .              .              .198 

Saline  manures,    .....  204 

Sulphate  of  soda  as  manure,  .             .              .       204- 

Sulphate  of  lime,  or  gypsum,  as  manure,   .  .              205 

Silicates  of  potash  and  soda  as  manures,  .             .206 

Salts  of  ammonia  as  manure,         .  .             .              206 

Screw,            .             .  .             .             .       234 

T 

Tenacity,          .             .             .  .             .             .28 

Tannin,       ......  64 

Tertiary  strata,             .             .  .             .             .78 

Transition  rocks,     .             .             .  .             .                78 

Tissue,  cellular             .             .  .             .             .95 

Tissue,  woody         .              .              .  ...                95 

Tissue,  vasiform            .             .  .             .95 

Tissue,  vascular      .....  95 

Tissue,  laticiferous        .             .  ...             .96 

Tendrils,    .  120 


INDEX.  279 

Trade  winds,  -.    .                     .            ...  .       144 

Trachyte,                .....  83 

Tap  root,          .             .             .             .             .  .103 

Tuberous  roots,       .             .             .             .      *  104 

Trees, 107 

Temperature,  table  of         .             .             .             .  130 

Thunder,          ......       141 

Thunder,  cause  of               .             .             .             .  141 

Tornado,           .             .             .             .             .  .145 

Tillage,  varieties  of             .             .             .             .  177 

Tillage,  objects  of                     .             .             .  .177 

Trench  ploughing,               .             .             .             .  178 

Tanner's  bark  as  manure,         .             .             .  .198 

Top  dressing  for  crops,       .             .             .             .  199 

u 

Urine  as  manure,         .  .  .  .  .196 

Urine,  waste  and  value  of  .  .          .  .  197 

V 

Vein, 76 

Variety  defined,      .....  94 

Veins,               ......  112 

Venation,                .             .             .  .          .             .  112 

w 

Water,  .  .  .  .  .  .46 

Wax,          ......  61 

Wood, 107 

Weather,    ......  125 

Whirlwind,       .  .  .  .  .  .145 

Warping,    .  .  .  .  .  179 

Wood  ashes  as  manure,  ....       206 

Wheel  and  axle,     .  .  .  .  ,  234 

Wedge,  ......       234 

Winds,       ....  .  .  142 

Wool  as  manure,         .  .  .  ,  .192 

x 

Xanthine,  .....  64 

¥ 
Yeast,  .... 


• 


67829 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


